Dawn and Lisa Whiting, who went through a gay "marriage" ceremony at a pub last October, have already sparked a furious outcry from pro-family campaigners who accuse them of acting against nature and their children's future welfare.
Lisa Whiting, 24, a former RAF cook, conceived her baby daughter Terri, aged five months, using a syringe to extract sperm stored in a pickle jar. Her partner Dawn, a 21-year-old amateur boxer, is now four months pregnant after using the same method.
Now the Child Support Agency wants to track down the two men who donated their sperm to make them pay maintenance because Lisa and Dawn are living on state benefits.
A CSA spokesman said: "Child support legislation requires any parent, with care of a child who is in receipt of certain benefits, such as income support, to cooperate with the agency in naming the absent parent." A parent who does not co-operate risks having their income support cut by 40 per cent.
The women would not have been targeted by the agency had their pregnancies resulted from sperm donation from a licensed fertility clinic. Dawn Whiting had been turned down for NHS treatment and the couple could not afford treatment at a private clinic.
The CSA said that tracking an absent father did not begin until a child was born but Lisa Whiting will soon come under pressure to name her daughter's father. She is understood to be reluctant to do so because she does not want him to seek access on his release from prison, where he is serving a sentence for arson and burglary.
A spokeswoman for Stonewall, the gay rights group, said the organisation "supported absolutely" the right of the two women to live together as partners and found a family. But Dawn Whiting was being unfairly discriminated against simply because she was unable to afford private treatment at a licensed clinic. "We think it should be possible for a lesbian couple to contract to be the two parents, just like heterosexual parents with fertility problems."
The couple, who share a home in Peterborough, Cambridgeshire, strongly defended their decision to opt for DIY insemination. "Our daughter Terri Leigh Ann is getting a good upbringing and we have nothing to be ashamed of," Dawn told their local paper, the Evening Telegraph. "It will be the same with the new baby. We have a loving and stable relationship in which to bring up children.
"We wanted a sister or brother for Terri Leigh Ann and we didn't want there to be a big age gap between them. We want Terri to go out with boys. If I have a son he'll go out with girls. We're not going to give them what you would call a gay upbringing."
But some pro-family groups were shocked. Yvonne Stayt of Concern for Family and Womanhood said: "It's devilish, absolutely disgusting and against nature."