Neil Patrick Harris confesses he has no interest in knowing which of his twins is biologically his

Neil Patrick Harris revealed that he is not interested in finding out which of his twins is biologically his.

The star of Netflix's A Series of Unfortunate Events and his husband, David Burtka, had twins Gideon and Harper via surrogate in 2010.

The couple - who tied the knot in September 2014 - have previously opened up about the process of becoming parents.

This involved taking a sperm sample from each of the two dads-to-be and fertilizing two eggs, one with each sample.

After this, the two eggs were then implanted into a surrogate who would carry the baby to term, with the donors of the eggs remaining anonymous.

Except in the case of Patrick Harris and Burtka it ended up being 'babies' as both eggs went to full term. This meant that each of the two men has a 'biological' child, but they don't know which is which.

Explaining the process, the How I Met Your Mother actor said that both he and Burtka had wanted to become a biological parent.

Neil Patrick Harris and David Burtka have been married since September 2014. (Frazer Harrison/Getty Images)

Speaking to American broadcaster and journalist Barbara Walters in 2014, he said: "We inserted one of my sperm and one of David's sperm into two eggs with the hope that they would both take, just because we both wanted to be dads biologically.

"Both took, miraculously.”

The twins were born in 2010, and are now both 13 years old.

And despite both of them wanting to become a parent biologically, Patrick Harris made it clear that he has no interest in finding out which of the twins is his biological child.

He told Walters: "I have no interest in [finding out]. We are their parents and I love them implicitly.”

The process of surrogacy means that Gideon and Harper are not identical twins, where a fertilized egg splits into two foetuses, but fraternal twins. This is where multiple eggs are fertilized during conception and both manage to successfully begin gestating in the womb.

The actor said he is not interested in finding out which twin is his biologically. (Cindy Ord/Getty Images for Tribeca Festival)

While they can occur naturally, fraternal twins are more common when a form of fertility treatment is being used.

For example, during In-Vitro Fertilisation (IVF) multiple fertilized eggs are implanted into the womb. This is done to increase the chances of a successful pregnancy over implanting one at a time.

But because more than one is implanted, sometimes more than one egg can begin gestating resulting in fraternal twins.

Patrick Harris and his family frequently catch people's eyes with their retro-style family Christmas cards.

In October 2023, he shared a heartwarming post for the twins' 13th birthday.

Patrick Harris wrote in the caption: "And, just like that, they're teenagers.

“Happy birthday, Harper and Gideon.

“You are the lights of my life. I can’t wait to watch you want nothing to do with me, and I promise I’ll be with you through all of it.”