A lesbian in Ohio, US, has lost a custody battle over the biological daughter of her former partner.

Michele Hobbs and Kelly Mullen had lived together in Cincinnati and made the decision to become parents before Ms Mullen gave birth to the child, Lucy, in 2005.

The couple had taken out a second mortgage together to fund costly fertility treatment and until the couple split, Ms Hobbs shared parenting duties and financial support.

However, when the relationship broke down two years later, Ms Mullen revoked Ms Hobbs’ rights as a co-parent.

According to reports, she had referred to Ms Hobbs as a co-parent in documents, indicating that she wanted the other woman to have full parental rights over Lucy.

Ms Hobbs argued that these documents showed the pair were in a contractual agreement.

But Ohio’s Supreme Court heard that Ms Mullen had repeatedly refused to state those wishes in a binding legal document.

Upholding previous rulings made by lower courts, Supreme Court judges ruled 4-3 that Ms Hobbs had no rights over the girl.

Legal experts watching the case pointed to the need for legal protection for non-biological parents or guardians.

Christopher Clark, a senior staff attorney at LGBT group Lambda Legal, said: “This decision is a tragedy for the child, above all else.

“The court disregarded the overwhelming evidence that Ms Mullen agreed to parent Lucy with Ms Hobbs ‘in every way.’ Regrettably, the decision severs a parent-child relationship between Lucy and the person she knows to be her mother. “

He added: “All Ohio families should be alarmed by this, as a child with a non-biological parent could be taken from their mom or dad in the event of a separation.”