Private eyes should have the same motto as Boy Scouts-Be Prepared. If I had to pass on one secret to any aspiring PI, that's what it would be. With that in mind, I settled down in my half of the conservatory with breakfast and the printed version of Sarah Blackstone's case notes. I needed to look more closely at the idea of her former col-leagues having a motive for murder. If I was going to grip them by the lapels of their lab coats, thrust them against the wall, and apply the red-hot pincers to treasured parts of their anatomy, I wanted to be sure I was asking the right questions.

Armed with the background information I'd picked up from the boy wonder of St. Mary's, this time I was able to make a lot more sense of what I was reading. And it was the kind of sense that made the hairs on the back of my neck stand up. I flicked back through the pages to check that I wasn't misunderstanding what I saw in front of me. But there was no mistake. If I'd been short of motives for Sarah Blackstone's murder before, I was awash with them now.

Women tend to assume that it's only male doctors who are sufficiently arrogant, overbearing, and insensitive to ride roughshod over their patients' lives. Wrong. Overexposure to these charming traits during training obviously rubs off on a lot of the women who go the distance too. However pleasant, supportive, and discreet Dr. Black-stone might have appeared to the women who consulted her, scratch the surface and she was as bad as the worst of her profession. The women who had trusted her hadn't so much been patients as the subjects of her experiments. That was the message that came through loud and clear from her notes.

It wasn't enough for her that she'd been breaking new ground by performing miracles that women had never had the chance to experience before. Like so many of her male colleagues down the years, she wanted a different kind of immortality. What her notes told me was that she'd been playing a kind of Russian Roulette to achieve it. She had been harvesting her own eggs for as long as she'd been treating other women. The notes were there; she'd persuaded one of her colleagues to do the egg collection, on the basis that Sarah was going to donate the eggs to women who couldn't produce fertile ones of their own. I knew now from my own research that because of the courses of fertility drugs involved in producing half a dozen eggs at once, she'd only have been able to harvest her own eggs two or three times a year. But that had been enough. Although she couldn't use her own eggs exclusively in the mix, she had been including one of her own eggs with each couple's batch. She'd have let four or five embryos develop for each couple, and returned three of them to the womb. For every woman she'd successfully impregnated, there was a one in four or five chance that the baby was not the child of the mother and her partner. Instead, it would be the result of a genetic mixture from the mother and Sarah Blackstone. And Chris was pregnant.

It was a nightmare, and one that I absolutely couldn't share with my client. And if I couldn't tell my best friend, there was nobody else I could dump on either. Certainly not Richard. After the recent rockiness of our road, the last thing he needed to hear about was the potential redundancy of the male. But it wasn't just the implica¬tions for Chris's pregnancy that bothered me. It was the long-term dangers within the gene pool. Judging by what I knew from Alexis, a lot of lesbian mothers in Manches¬ter formed a close-knit social group, for obvious reasons. Their kids played together, visited each other's houses, grew up together. Chances were by the time they were adults, two women making babies together would be accepted medical practice, not some hole-in-the-corner criminal activity. What would happen if a couple of those girls fell in love, decided they wanted to make babies, and they were half-sisters because they'd both come from Sarah Blackstone's eggs? Either they'd find out in prelim¬inary genetic tests, or, even worse, they'd start a cycle of inbreeding whose consequences could poison the future for children not yet imagined, never mind conceived. It was a terrifying thought. But it didn't surprise me that it was a possibility on the horizon. When society sets things up so that the only way people can achieve their dreams is to go outside the law, it automatically loses any opportu¬nity to control the chain reaction.

It was also an experiment that wasn't hard to unravel. Any of the couples who were looking at a child who didn't look a bit like either of them but had a striking resemblance to their doctor wasn't likely to be handing out the benefit of the doubt. It's not impossible to have private DNA testing done these days, and at around five hundred pounds, not particularly expensive either, compared to the cost of IVF treatment and the expense of actually hav¬ing a child. A few weeks and the couple would have their answer. And if the mother's partner wasn't the biological co-parent, you wouldn't have to be a contender on "Mas¬termind" to work out that the chances were that the other egg had come from the person most concerned with the procedure.

The more I found out, the more the idea of a random burglar sounded as likely as Barry Manilow ducting with Snoop Doggy Dogg. Forget her colleagues in Leeds. They'd still be there tomorrow. Right now, I needed to check on whether there was a murderer on my own doorstep.

Lesley Hilton was Sarah Blackstone's first experiment mother. According to the files, she lived with her partner on the edge of the Saddleworth moors, where the red¬brick terraced slopes of Oldham yield to the Yorkshire stone villas built by those of the Victorians who managed to get rich on the backs of the ones toiling in the humid spinning mills. It was far from the nearest address to me, but Lesley's daughter Coriander must be around eighteen months old by now, and if she was Blackstone's baby, it might be obvious. It was as good a place to start as any, and better than most.

The house was one of a group of three cottages set at the foot of a steep field where sheep did the job I'd have cheerfully paid a gardener to do. Anything's preferable to having a herd of wild animals at the back door. The original tawny color of the stone was smudged with more than a century's worth of grime. So much for the clean country air. I yanked an old-fashioned bellpull and heard a dispro¬portionately small tinkle.

The woman who opened the door looked like a social worker in her fisherman's smock, loose cotton trousers, and the kind of sensible leather sandals that make Clark's Startrite look positively dashing. She was short and squarely built, with dark blond hair cut spiky on top. She peered at me through granny glasses, her chubby face smiling tentatively. "Yes?" she said.

I'd been working on a decent cover story all the way out along the Oldham Road. What I had was pitifully thin, but it was going to have to do. "I wonder if you could spare me a few minutes?" I started. "This isn't easy to talk about on the doorstep, but it concerns a Dr. Sarah Blackstone."

Either Lesley Hilton had never heard the name before, or she had more acting skills than a family outing of Red-graves. She looked blank and frowned. "Are you sure you've got the right house?" "You are Lesley Hilton?"

She nodded, her head cocked in what I recognized as the classic pose of a mother listening for a toddler who was probably dismantling the TV set as we spoke.

"I think you probably knew Dr. Blackstone as Dr. Helen Maitland," I said.

This time, the name got a reaction. Her cheekbones bloomed scarlet and she stepped back involuntarily, the door starting to close. "I think you'd better go," she said. "I'm no threat to you and Coriander. I'm not from the authorities, I swear," I pleaded, fishing out a card that simply said, "Kate Brannigan, Confidential Consultant," with the office address and phone number. I gave her the card. "Look, it's important that we talk. Dr. Blackstone or Dr. Maitland, whatever you prefer to call her, is dead and I'm trying to..."

The door closed, shutting off the expression of panic that had gripped Lesley Hilton's features. Cursing myself for my clumsiness, I walked back to my car. At least I hadn't blown it with someone who knew that Dr. Helen Maitland was really Sarah Blackstone. I'd have put money on that. And if she wasn't aware of that, chances were she hadn't killed her.

I fared better with Jude Webster, another of the early births. According to the files, she'd been a self-employed PR copywriter when she became pregnant. Judging by the word processor whose screen glowed on the table next to the pack of disposable diapers, she was still trying to earn some money that way. She had glossy chestnut hair, which, considering the depth of the lines around her eyes, owed more to the bottle than to nature. Even though little Leonie was at the nursery, the buttons on Jude's cardigan had been done up in a hurry and didn't match the appropriate buttonholes, but I didn't feel it would help our rapport if I pointed that out.

The news of Sarah Blackstone's real identity and her death had got me across the threshold. I hadn't even needed a business card. Maybe she assumed I was another of the lesbian mothers come to bring the bad news. "I'm sorry," she now said, settling me down with the best cup of tea I'd had in weeks. "I didn't catch your connection to Dr. Maitland... Dr. Blackstone, I mean."

Time for the likeliest story since Mary told Joseph it was God's. "As you know," I started, "Sarah was a real pioneer in her field. I'm representing women who are concerned that her death doesn't mean the end of her work. What we're trying to do is to put together a sort of casebook that those who follow in her footsteps will be able to refer to. But we want it to be more than just her case notes. It's an important piece of lesbian history. The experience of the women who led the way mustn't be lost."

Jude was nodding sympathetically. She was going for it, all the way. Pity she had acted totally blank when I'd first mentioned the name Sarah Blackstone. "You're so right," she said earnestly. "So much of women's achievements and contributions just get buried because the books are written by men. It's vital that we reclaim our history. But..."

"I know, you're concerned about confidentiality," I cut in. "And let me tell you, I can fully appreciate why. Obvi¬ously, the last thing my clients want is for people's privacy to be compromised, especially in circumstances like these. It wouldn't serve anyone's interests for that to hap¬pen. But I can assure you that there will be nothing in the finished material to identify any of the mothers or the children."

We danced around the issue of confidentiality for a bit, then she capitulated. My granny Brannigan always remarked that I had an honest face. She said it made up for my devious soul. Within an hour, Jude had told me everything there was to tell about the consultations that she and her partner Sue had had with Dr. Blackstone. And it was all a complete waste of time. The first two minutes with the photograph album revealed a child that was the image of Sue, right down to an irrepressible cowlick above the right eye that wouldn't lie down and die. This time, Sarah Blackstone had missed.

By late afternoon, I knew the laws of probability had been on the doctor's side. But then, aren't they always? Ask anybody who's ever tried to sue a surgeon. At least two of the kids I'd seen bore more than a passing resem¬blance to the dead doctor. I was astonished the parents didn't seem to notice. I suppose people have always looked at their children and seen what they wanted to see. Otherwise there would be even more divorces than there are already.

At ten to five, I decided to hit one more and then call it a day. Jan Parrish and Mary Delaney lived less than a mile away from me in a red-brick semi on what had once been one of the city's smarter council housing estates. When the Tories had introduced a right-to-buy scheme so loaded with inducements that anyone in employment would have had to be crazy to say no, this estate had fallen like a line of dominoes. Now finding a resident who still paid rent to the council was harder than finding food in Richard's fridge.

Porches, car ports, and new front doors had sprouted rampantly with no regard to any of their neighbors, each excrescence an indicator of private ownership, like a dog pissing on its own gatepost. Jan and Mary were among the more restrained; their porch was a simple red-brick and glass affair that actually looked as if it were part of the house rather than bolted on as a sad afterthought. I rang the bell and waited.

The woman who answered the door had an unruly mop of flaming red hair. It matched perfectly the small girl wrestling for freedom on her hip. I went through the familiar routine. When I got the part where I revealed the doctor's real identity, Jan Parrish looked appalled. "Oh my God," she breathed. "Oh my God."

It was the first time I'd struck anything other than cracked plastic with that line. And that was even before I'd told her Sarah Blackstone was dead. "It doesn't get any better," I said, not sure quite how to capitalize on her state. "I'm afraid she's dead. Murdered, in fact."

I thought she was going to drop the baby. The child took advantage to abseil down her mother's body and stumble uncertainly toward me. I moved in front of her, legs together and bent at the knees like a hockey goal¬keeper, and blocked her escape route. Jan picked her up without seeming to be aware of it and stepped back. "You'd better come in," she said.

The living room was chaos. If I'd ever considered motherhood for more than the duration of a movie, that living room would have put me off for life. It made Richard's mess look structured. And this woman was a qualified librarian, according to her medical record. Wor¬rying. I shoved a pile of unironed washing to one end of a sofa and perched gingerly, carefully avoiding a damp patch that I didn't want to think too closely about. Jan deposited the child on the carpet and sat down heavily on a dining chair with a towel thrown over it. I was confused; I couldn't work out what Jan Parrish's excessive reaction to my exposure of her doctor's real identity meant. It didn't fit my expectation of how a killer would react. I couldn't see Jan Parrish as a killer, either. She didn't seem nearly orga¬nized enough. But she had been horrified and panicked by what I'd said and I needed to find out why. Playing for time, I gave her the rigmarole about lesbian history. She was too distracted to pay much attention. "I'm sorry it's been such a shock," I said finally, trying to get the conversation back on track.

"What? Oh yes, her being murdered. Yes, that's a shock, but it's the other thing that's thrown me. Her not being who she said she was. Oh my God, what have I done?"

That's exactly what I was wondering too. It wasn't that I was too polite to say so, only too cautious. "Whatever it was, I'm sure it had nothing to do with her death," I said soothingly.

Jan looked at me as if I was from the planet Out to Lunch. "Of course it didn't," she said, frowning in puz¬zlement. "I'm talking about blowing her cover with the letter."

I knew the meaning of every word, but the sentence failed to send messages from my ears to my brain. "I'm sorry... ?"

Jan Parrish shook her head as if it had just dawned on her that she had done something so stupid that even a drunken child of two and a half would have held fire. "We were all paranoid about security, for obvious rea¬sons. Dr. Maitland always impressed on us the impor¬tance of that. She told us never to write to her at the clinic, because she was afraid someone might open the letter by mistake. She said if we needed to contact her again, we should make an appointment through the clinic. But we were so thrilled about Siobhan. When she had her first birthday, we both decided we wanted Dr. Mait¬land to know how successful she'd been. I'm a librarian, I'm back at work part-time, so I looked her up in Black's. The medical directory, you know? And it said she was a consultant at St. Hilda's in Leeds, so we sent her a letter with a photograph of Siobhan with the two of us and a lock of her hair, just as a sort of keepsake. But now you're telling me she wasn't Dr. Maitland at all? That means I've exposed us all to a terrible risk!" Her voice rose in a wail and I thought she was going to burst into tears.

"When was this?" I asked.

"About three months ago," she said, momentarily dis¬tracted by Siobhan's sudden desire to commune with the main electricity supply via a plug socket. She leapt to her feet and scooped up her daughter, returning her to the carpet but facing in the opposite direction. Showing all the stub¬bornness of toddlers everywhere, Siobhan immediately did a five-point turn and crawled back toward the skirting board. This time, I took a better look at her face. The hair might be Jan Parrish's but the shape of her face was unmistakable. I wondered whether Helen Maitland had also noticed.

"Well, if you haven't heard anything by now, I'd think you're all safe," I reassured her. "What did the letter actu¬ally say?"

She frowned. "I can't remember the exact wording, but something like, 'We'll never be able to thank you enough for Siobhan. You made a dream come true for us, that we could really share our own child.' Something along those lines."

"I wouldn't worry about it," I said. "That could mean anything. It certainly wouldn't make anyone jump to the conclusion that something so revolutionary was going on. And it doesn't give any clue as to who was actually treat¬ing you, does it? Unless the real Helen Maitland knew Sarah Blackstone was using her name, she's got no way of guessing. And if she did know, then presumably, she was in on the secret too. I really don't think you should worry about it, honestly," I lied. I wanted to grab her by the shoulders and shake her for her stupidity. With a secret that held as much threat for her and her daughter, she should never have taken so outrageous a risk. Given that her mother faced a lifetime of discretion, I didn't rate little Siobhan's chances of making it to adulthood without being taken into care and treated like an experimental animal in a lab. Instead, I made my excuses and left.

I hadn't found a serious suspect yet among the women who had been Sarah Blackstone's patients. I hoped I'd still be able to say that when I'd finished interviewing them. I cared far too much for Alexis and Chris to want to take responsibility for the hurricane of official and media attention that would sweep through their lives if I had to open that particular corner of Sarah Blackstone's life to public scrutiny.

Sometimes I think Alexis is psychic. I'd driven home thinking about her, and there she was on my doorstep. But it only took one glimpse of her face to realize she hadn't propped around to say how gratified she was at my concern for her. If looks could kill, I'd have been hanging in some psychopath's dungeon praying for the merciful end that death would bring.