A surrogate mother who is pregnant with twins has found herself in an extraordinary situation after being told one of the babies actually belongs to her.

Courteney Williams, who volunteered to help a couple achieve their dream of starting a family, unknowingly conceived naturally with her husband just days before doctors implanted the hopeful pair’s embryos.

The unusual discovery has left both couples stunned, but Ms Williams says everything was done above board.

‘Honestly I have never been so shocked in all my life,’ she said. 

‘It’s all legal, it’s gone through the Queensland board of surrogacy, it was all approved, we did lawyers, counsellors and all the right things. We followed every rule.’

Ms Williams said the unusual situation came about after she had sex with her FIFO husband Ethan while using a condom, 11 days before she was due to ovulate.

‘I’m not an idiot, I know how babies are made,’ she said in a TikTok video.

‘I randomly ovulated on day 15 for the first time in my life, but since intercourse was still five days earlier and we used protection it was not a concern.

‘It is possible to conceive, but the chances were so low that it wasn’t even considered as an issue or a problem.’

The embryo transfer then went ahead on day 20.

Ms Williams last year decided to become a surrogate after giving birth to five healthy children of her own.  

‘We did not know this couple prior to the surrogacy journey,’ she said.

‘We met through a mutual friend who knew I wanted to be a surrogate and knew they wanted a surrogate.

‘So it was like a matchmaking thing. But they are now our really good friends.’

Ms Williams also explained surrogacy in Australia is altruistic, which means she receives no payment and that contracts drawn up are not legally binding.

‘I don’t get any benefit from it except for giving someone the gift of bringing their baby into the world, which is amazing and enough for me,’ she said.

Courteney Williams was shocked to find one baby actually belongs to her

Courteney Williams was shocked to find one baby actually belongs to her

‘Contracts are more along the lines of the surrogate agreeing to carry the intended parents’ embryo resulting in live birth, and the surrogate agrees to give the intended parents that baby.

‘There is no contract about intimacy and things like what I can or can’t do with my body.’

Ms Williams said because she has always had a 34-day cycle, the doctors followed a ‘natural protocol,’ timing the embryo transfer with her ovulation.

She had been trying to conceive the surrogate baby for six months and was elated when she returned a positive pregnancy test a few weeks later.

But during the 11-week scan it was noted that the babies did not look identical which meant it was likely they had not come from a split embryo. 

Then at the 16-week scan it was confirmed that the babies were not the same gender.

‘If an embryo splits the twins have to be identical so being different genders indicated they were not,’ she explained. 

‘The couple had their embryos genetically tested prior to the transfer so the clinic knew the gender of their baby.’  

She had been trying to conceive the surrogate baby for six months

She had been trying to conceive the surrogate baby for six months

Ms Williams says both the babies will be DNA tested once they are born

Ms Williams says both the babies will be DNA tested once they are born

Referring to the babies as ‘womb mates,’ Ms Williams said people now ask her who will keep them.

‘To me that’s pretty obvious, I would keep my baby and they would keep their baby,’ she said.

‘The babies will be friends and will know each other and hopefully grow up together as friends.

‘Of course, we will be DNA testing them after birth regardless, because when you go to court and they adopt their baby from me and my husband, you need DNA to show that’s their baby.’

Ms Williams is now 22 weeks pregnant, with both babies due in December.

‘It’s been the wildest emotional rollercoaster but I wouldn’t change it for the world,’ she said. Â