Another gay man is fighting a lesbian couple to gain access to the child he helped them have.

Stacey Cassin, 24, and her civil partner Kate, 26, advertised online last year for a sperm donor because they could not afford treatment at a clinic.

Mark Hartill, 30, replied to the ad and Kate became pregnant with his help.

The women claimed that they had a “gentleman’s agreement” that he would not be involved with the baby’s upbringing.

But the couple told The Sun that he had become “besotted” with the baby girl after seeing her several times and now wants weekly access to the child and to be recognised as a parent.

Stacey claimed he had broken their “verbal agreement”.

She added: ”We are determined to fight this through the courts, though we never wanted it to come to this.”

Mr Hartill told the newspaper that the matter was private and he did not want to say anything to prejudice the case.

Last week, a gay father won joint custody of the seven and ten-year-old children he had with a lesbian couple.

The couple found the man through an ad in a gay magazine, in which he said that he wished for “a little involvement” as a father.

The Court of Appeal upheld an order giving him custody of the children for 152 days a year.