Two lesbians have become the first same-sex couple in the United Kingdom to list both their names as parents on the birth certificate of a baby conceived through in vitro fertilisation.

The listing of two people of the same sex as parents breaks with country’s nearly 200-year birth certificate tradition, in which only the birth mother could be listed as the parent since she was not given the name of the male donor. Her partner would have to go to court and argue her case to be listed as the other parent.

But Natalie Woods, who gave birth to Lily-May on March 31, and her partner Betty Knowles, were both listed as parents because of the 2008 Human Fertilisation and Embryology Act, which took effect in early April. Under the new act, the words “mother” and “father” have been dropped from birth certificates.

“Birth certificates should reflect how a baby is generated,” Josephine Quintavalle, from Comment on Reproductive Ethics, told The Telegraph. “In a culture that is obsessed with genetics, it is strange that when it comes to birth certificates we are prepared to forget all that.

“As much as you try to play around with the terminology, the biology reflects what has happened and one day the child will ask about their father.”

Similarly, Baroness Ruth Deech, chairman of the Bar Standards Board, has criticised the rule allowing same-sex couples to sign birth certificates without mentioning the father.

“There is an issue of principle here, which is the truth,” Deech said last month. “This is not a moral issue; it is about disguising true facts, and it is about confusing biological parenthood, legal and social parenthood.”

Deech also said the new rule “puts the demands of the adults ahead of the rights of children to know and benefit from both sides of their genetic makeup”.

According to The Daily Mail, the couple has decided that Lily-May will call Woods “Mummy” and Knowles “Mama B”.

Woods works for a lesbian, gay, bisexual and transgender counselling service while Knowles is a delivery driver. The two women have been together for 16 years and plan to have a civil partnership in the near future.

“It is fantastic, quite a milestone,” Woods told The Telegraph. “Compared to having to go through the courts, this is really straightforward and the way it should be.”

She added, “The fact that same-sex parents can both be on the birth certificate shows our kind of family is becoming more acceptable.”