But having a black child in an all-white household is entirely different from one with one black parent. Did they not consider this? "We know people from every ethnic background, more or less, and we talked about how our baby would have black and white positive role models." Talking to both women gives me the impression that they chose a black donor for aesthetic reasons as much as their commitment to anti-racism. "Our child is beautiful," says Lisa. "She has the most gorgeous curly hair and beautiful skin."

The UK's first fertility organisation to accept gay donors is Man Not Included (MNI), established in 2002. It advertises itself as the "world's only confidential and anonymous sperm donation service". Its opening paragraph reads like a human rights mantra, rather than a plug for a commercial service. "Mannotincluded.com believe that it is every woman's right to have children if they so wish and that is why we [are] open to any woman, be she single, lesbian or married." Founder John Gonzales said: "A few years ago, we would have struggled to get such good business, but today, it is totally accepted that lesbians should be able to have children if they wish." MNI is no longer trading but there are scores of other similar services based in the UK and US catering specifically for lesbians. A number of websites give hugely detailed profiles of the donors, including all physical and intellectual profiles, hobbies and personality traits. 

While some lesbians and gay men are spending a fortune trying to bring another baby into the world, it costs an estimated £700 a week to keep one child in care. 

Although many heterosexual men and women will choose a spouse on the basis of the sort of looks and characteristics they wish any future children to inherit, "gaybe" boomers can shop around far more widely. Lesbian couple Sharon Duchesneau and Candy McCullough, both deaf since birth, made headlines in 2002 when they were turned down by a series of sperm banks they approached looking for a congenitally deaf donor. Refusing to give up, the couple then approached a family friend who had five generations of deafness in his family and was deaf himself and asked him to donate sperm. The result was a deaf baby. McCullough said in response to her critics at the time that choosing to have a deaf child was no different from choosing its sex. 

Much of the market is determined by race. Surrogates tend to be black or Asian and the donors white. India was recently named as the "rent-a-womb capital of the world" in a report on Slate.com. "Reproductive tourism" is now a half-a-billion-dollar a year industry, with 350 clinics offering surrogacy around the country. There it is barely regulated and cheap, costing just over $22,000 compared to around $100,000 in the US. For the desperately poor surrogates, bearing someone else's child is a better option than selling a kidney. Interestingly, the surrogates are almost exclusively Muslim, whereas the egg donors used by Asian couples (white intended parents will fly an egg donor of their choice to India for the procedure) are Hindu. 

Is it really acceptable that wombs are rented and eggs sold on the open market? Not according to the World Health Organisation, which takes a dim view of this commercialisation of childbirth, as do many children's charities. 

To date, the only criticism of the designer "gaybe" industry has come from those who believe that same-sex couples should not be allowed to bring up children. Those within the lesbian and gay communities seem to be largely uncritical of rich, white gays exploiting the bodies of poor, desperate women in the developing world, or adding to the "rent-a-womb" industry elsewhere. 

The reasons for same-sex couples opting for surrogacy and other fertility services are partly the culture of homophobic oppression and partly related to biological constraints. But the fact remains that such practices are becoming so normalised and available that we will soon forget that designer babies grow up to be questioning adults.