A Canadian court has ruled that a gay man who is not the biological father of a 10-year-old girl is nevertheless her legal father.

The ruling, made by the Court of Appeal in the Canadian province of Alberta, found that, even though the girl’s biological father was the plaintiff’s former partner, the plaintiff, described as Mr H to protect the girl’s identity, had a right to be regarded as a legal parent, the National Post reports.

The man raised her with his partner, Mr. R, for the first three years of her life, and the court, upholding an earlier ruling by a lower court, held that the part of Albertan family which denied him – and any other non-biological father who is not married to the mother – the legal status of “parentage based on intent,” was discriminatory.

The girl lives with Mr. R, her guardian, and this new decision has no effect on her custody arrangements, though it gives Mr. H standing to challenge them.

The decision to name Mr. H her legal father, upheld by Alberta’s top court last week, follows the acrimonious breakup of the men’s “marriage-like” relationship, which upended an arrangement they had with the mother, Ms. D, and her lesbian partner, Ms. C.

Born in May 2003, the girl lived with the men, calling them Papa and Daddy, and the women had regular contact. Under their arrangement, a second child was conceived, a boy, who is being raised by the women.

When the men separated in 2006, Mr. R and Ms. D drew up a new agreement in which they were both guardians, with Mr. R having primary custody.

Initially, they denied access to Mr. H, who applied to the court for parental contact, which was denied after discussion of his HIV positive status, his “irrational and emotional” behaviour following the breakup, and the fear that the girl would be confused if forced to see him.

On appeal, he won access pending trial, but the relationship with Mr. R worsened. Since 2007, the lower court judge wrote, Mr. H’s relationship with the child has been “virtually non-existent.”

A trial took place in 2009, with the result that the child legally had only a mother, Ms. D, who did not have primary custody. The next year, Mr. R., who had continued to raise the child, became her legal guardian with Mr.H’s consent.

Mr. H then challenged the province’s Family Law Act which, as a judge found, “bases male parentage on the existence of a spousal or common-law relationship with the birth mother; an occurrence that will never be realised in a same-sex relationship.”

His victory marks the latest, though not likely the last, in a long line of controversial legal cases about the nature of parenthood, which has shifted according to scientific changes.

Among the lifelong rights and obligations that come with parentage are that a Canadian parent may confer citizenship regardless of where the child is born; a parent must consent to any future adoption; and a parent may register a child in school or obtain documentation, such as a passport or health card, on behalf of the child.

In the 1970s, legislatures across Canada moved to abolish the notion of illegitimacy.

From then on, a person’s status as a child of their parents did not depend on being born into wedlock. Likewise, the legal presumption that the husband of the mother is the father of the child has fallen out of favour, as it fails in the case of surrogacy.

Birth certificates are routinely changed in all provinces, to correct mistakes or reflect adoptions, and declarations of parentage are relatively common, but are usually about paternity. Declarations about maternity are very rare, but have happened. In 2011, for example, a Saskatchewan judge ruled that a woman who gave birth to a baby girl is not actually the child’s mother, because she carried it as a surrogate and surrendered all parental rights at birth.

In 2002, an Ontario judge likewise declared a gestational carrier was not the mother of a child, largely because the carrier gave her consent to the arrangement.

In 2000, a Manitoba judge ruled in the case of a woman who was a gestational carrier for her sister-in-law’s ovum, fertilized with her brother’s sperm. The judge refused to declare the sister-in-law to be the mother of the as yet unborn child, and declined to make an order about paternity to avoid the uncomfortable outcome of siblings being listed as parents.

And in 2007, the Ontario Court of Appeal declared a child to have three parents under the law: Her biological father and mother, and her mother’s same-sex partner, all of whom were actively involved in the child’s life.