So you want a baby but there's no sign of Mr Right...

What are you going to do to beat the biological clock? As more women find themselves single in their thirties, Emma Cook discovers that donor insemination is producing a new baby boom

Sarah, 37, is a stockbroker and single. Her last long-term relationship finished two years ago. She doesn't have to be reminded that time is ticking by at break-neck speed, her biological clock does it for her. Ten years ago Sarah, like so many thirtysomethings, imagined that life would have panned out differently by now, that there'd be man in the picture, a child as well, maybe two. Like Bridget Jones, she's getting on and she's getting anxious. But rather than settle for second best, like poor old Lesley Ash in Men Behaving Badly, she's chosen another solution.

"I've always definitely wanted a child, but unfortunately I haven't met Mr Right," says Sarah, who has spent more than pounds 20,000 on donor insemination (DI) treatment in the past two years. "If I get married, it will be to someone I want to spend the rest of my life with. Lots of my friends have settled for unsatisfactory relationships, so they can have children - it's the easiest thing to do."

She has also rejected the option of sleeping with a male friend. "I can't even kiss someone I don't fancy, let alone own do anything else," she says. "I've got loads of good male friends, but no matter how drunk I got, there's no way I could sleep with any of them." Also, there's no guarantee that one submission would suffice. For women in their late thirties, it could take a year of soulless one-night stands to do the trick. In this light, a monthly trip to a fertility clinic suddenly seems infinitely more desirable and practical. It's easy to see why Sarah views DI as more emotionally honest and straightforward. "I wouldn't want to get into a complicated situation with a male friend I knew. It's about settling for what I want."

Karen, 38 and a drama teacher, is also single and desperate to start a family. She is weighing up the advantages of donor insemination, but has reservations. "It's weird. My nightmare is that I'd end up with the child of someone completely undesirable. Also, I don't like the idea that you're buying something; putting your money down for some good sperm. It makes me feel uneasy." Instead, she has thought about asking a close male friend. "If I'm still in the same situation this time next year, I may well talk to him about it - not sleeping with him, but artificial insemination."

Last week, comedian Sandi Toksvig was quoted in the papers as saying artificial insemination was "incredibly easy". She is now separated from her long-term female partner, but her three children were conceived with the aid of a close male friend and a "10p syringe from Boots". Since the mid-Seventies, self-insemination has been a tried and trusted option for lesbians - there were self-help guides on the subject, such as Lisa Saffron's Getting Pregnant Our Own Way. As well as providing practical details of how to collect and insert sperm, guides like these made a political statement about taking reproductive control.

All this is a relatively new arena for the thirtysomething Lone Ranger - her fertility needs are increasingly similar but she has no overt political agenda. Instead, many single heterosexual women who want children view artificial insemination as the last resort - an option that somehow symbolises failure. "It seems so desperate to have to go to such extremes," says one single friend in her late twenties.

But ten years down the line, she could feel very differently. Already, there is a shift in attitude among the thirtysomething sector. Medical estimates indicate that about 300 women a year - 10 times the number five years ago - are becoming single parents. With monthly treatments costing between pounds 100 and pounds 500, perhaps it is the first time so many single professional women can afford it. But they are also seeing it as a more responsible scenario than, say, a short-lived fling or an unsatisfactory relationship that would probably end anyway. All the women I spoke to who underwent the treatment also agreed that one of the decisive factors was receiving sperm that had been screened rather than risking unprotected sex.

"Word is getting about more," says Emma Hopson at the Bridge Centre in London, a fertility clinic where 30 per cent of clients are single women. "But it's not the scenario of a woman being a careerist and not wanting to bother with a man. It's because they can't find suitable men. Quite often, they've come out of a serious relationship and they haven't met anybody else," she says. "I think it is a real alternative as more women become aware of the option." Professor Ian Craft at the London Gynaecology and Fertility Centre agrees. "Numbers at our centre have increased, perhaps because women know it's an accepted practice and not a fringe activity."

Yet many clinics are unwilling to treat single women, feeling that couples should be given first priority. With the fear of a decrease in sperm donees, these views are unlikely to shift, even though the Human Fertilisation and Embryology Authority have published guidelines which don't exclude single women. Professor Craft, who treats each case on an individual basis, says, "There is a responsibility to make sure the child will be looked after and that proper provision has been made if something happens to the mother."

Other clinics may shift their policy, though, as more couples are turning away from donor insemination and using a new male fertility treatment called ICSI. As one fertility insider explains, "This may mean that private clinics will lose business - then they could view the single woman as a new and desirable customer."

Still, in terms of attitudes, we are way behind our American counterparts who have already geared up to the full marketing potential of DI. A company called California Cryobank even offers a full delivery service for $85 to "ship to your home" where, supposedly, you can do it yourself. There are numerous support groups for "Single Mother's By Choice" and even a website with messages such as, "I am a single career woman that is possibly looking toward artificial insemination. I have nothing against a family household, but this is just an option I'm considering. Any help would be appreciated."

In Britain, the single women I interviewed felt they have had to remain quite discreet about their decision to choose DI. Sophie, 40, decided to have DI three years ago and still hasn't told her family exactly how she got pregnant. "I went through a fairly radical life-change at 35 years old. I had a serious illness and took stock of my life. One result was that I definitely wanted a child. I talked about the possibility of sex with two male men friends but it felt totally dishonest. It felt like using them - it wasn't the right way to do it."

So, she went for monthly treatments at a fertility clinic and became pregnant after three years. "It was emotionally draining and harrowing, like any fertility treatment. The difference is, in a couple, you're actually doing it with someone else, someone who's there to support you." Sophie also feels that her predicament is symptomatic of the Nineties, where a generation of women are facing up to the fact they want children but can't find a suitable partner. She says, "It's a difficult time to be a single woman in your late thirties and forties. I still don't think I'll meet someone. But at a certain stage, I just thought I've got to go for it on my own."

Which is why the Lone Ranger's desire for children will become even more controversial than the issue of lesbian parents. The singleton's decision to go-it-alone is, unwittingly, a far more blatant rejection of masculinity. While Toksvig and her partner went for the DlY option because, in practical terms, they had no other way of doing it, Sarah, Sophie and hundreds of women like them do. It's just that they weren't prepared to settle for second or third best. Sophie, now with a three-year-old daughter, says, "It really suits me. I expect an awful lot. I enjoy living on my own and I'm not prepared to compromise."

Donor insemination is usually administered to the uterus via the cervix. A woman undergoes the treatment, which takes about 20 minutes, once a month, at the most fertile time of her cycle. All sperm is medically screened and quarantined for six months, and donor receivers can state a preference for limited characteristics like hair colour, eye colour, height and build. It is rare for women to receive treatment on the NHS, but there are 105 private DI clinics in the UK. For more information, contact the DI Network on 0181 245 4369, or the infertility charity Child on 01424 732361.