But Andrea Woelke, a solicitor at Alternative Family Law, a firm that offers advice to gay and lesbian couples using IVF and surrogacy, says that many of the gay men he advises choose not to adopt. "Often my clients have considered adoption and fostering," says Woelke, "but the process is such an intrusive and long-winded one and if the children come to them aged three or older they can have problems."

Woelke says that he is noticing an increased number of gay men inquiring about surrogacy. "Lots more lesbian and gay couples are wanting children as it becomes increasingly acceptable. If you are choosing an egg donor then it is inevitable that you would start to consider the type of looks and character traits and abilities you would like your child to have. It is a built-in perk."

Class and racial divisions between surrogates, egg donors and the intended parents are stark. Surrogates tend to be working-class and have already had their own children, whereas the egg donor is likely to be a college student from a wealthy background who is considered bright and attractive. They earn more than the surrogates. In the US, the price of embryos is approximately $20,000. 

In 2007, The Fertility Institutes in Los Angeles announced that, due to popular demand, it would be running a programme aimed at providing surrogacy services to gay men. It immediately began to receive numerous inquires from male couples in Britain. The programme is the first specialist surrogacy scheme dedicated to "two-father" families. The men are able to choose whether to have boys or girls, with three-quarters so far opting for male babies. 

I spoke to one surrogate in the US, a 35-year-old housewife who asked not to be named because, she said, her parents would be "horrified" if they knew she made money from giving birth. "I was approached by a gay male couple last year who told me I was perfect for them because I had wide hips, like a brood-mare. I am now seven months pregnant and they come with me to every appointment and talk to my doctors on a regular basis. It is their baby. I have to follow their rules about what I eat and drink and how I look after myself."

Making babies the lesbian way has also become increasingly commercialised. Baby on Safari, set up seven years ago in Durban, South Africa, is part of the growing "Gaybe" revolution. It caters for overseas lesbian and gay couples who cannot "get a baby" in their own countries.

"Lesbians travel here from Australia, America and the UK," the woman who runs the service told me. "For them, even with the air fare and other expenses, it is still cheaper to get fertility treatment here than back home." 

BoS offers IVF treatment and has its own sperm bank. Men are catered for, too. If they want a baby, BoS will assist, so long as they bring their own eggs and surrogate mother to the clinic. "Lesbians want their own babies, and are thinking, ‘I can, therefore I want to.'" 

Kate and Lisa (not their real names) decided to start a family three years ago and signed up to a commercial donor company. Both white, they decided that it would be "ethically questionable" for them to request a donor of the same race and Lisa became pregnant with the sperm of a man of African origin. "I thought it may be racist in a way to exclude the possibility of a mixed-race child," says Kate. "After all, if I had met a black man and fallen in love I would have had dual-heritage children with him."