Three men have become the very first three-way relationship - or "throuple" - to have each of their names put on their child's birth certificate.

Ian Jenkins, Alan Mayfield, and Jeremy Allen Hodges have been in their unconventional but happy relationship for the best part of a decade.

Per The Mirror, they made legal history in 2017 when it was agreed in court that the California men could all be named as the fathers of their daughter, Piper.

And since three-year-old Piper's birth, she now has a one-year-old brother, Parker. The half-siblings were both born using an egg donor and a surrogate.

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Jenkins explained to HuffPost: "One of [Jeremy's] friends offered us the embryos they had left from making their family through IVF but couldn't use.

"We had the option to adopt the embryos and make the decision to raise a unique family.

"We did have a slight attention to the fact that our kids might be perceived differently. We didn't want them to become a target of teasing or bullying or online abuse.

"We've had zero pushback from anyone in our professional and personal lives. Our oldest now is in preschool, and the other parents and kids are like, 'Cool! Tell us that story.'"

In an interview with Australia's The Morning Show, Mayfield - who has been partnered with Jenkins for 17 years and Allen for eight - delved into the legal challenges of getting each of their names on their children's birth certificate.

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He said: "With surrogacy you have to have a parentage order from the court, declaring who will be the legal parents. At the beginning, we weren't sure that we could all three of us on the birth certificate, so it became a court process.

"We argued in court - it was a pretty interesting, tense courtroom scene. At first, it seemed we were not going to be granted that, so we asked to speak in court and pled out viewpoint and the judge ultimately changed her mind and granted us legal parentage for our child before she was born."

Jenkins has since written a book titled Three Dads and a Baby, which explores his and his partners’ journey to becoming first-time parents. It comes out in March 2021 and is available to pre-order now.

Men become first 'throuple' to have three fathers put on child's birth certificate