Writer Samuel Leighton-Dore, 25, spoke to Mirror Online about his decision for his sister to have his child - and has opened up about the negative response it has received.
Samuel, from Sydney, is in a relationship with photographer and designer Bradley Tennant but doesn't want to miss out on their baby having both of their family's genes.
As a compromise, his sister Bronte has agreed to donate her eggs so that the couple can have the family they've always wanted.
Samuel told Mirror Online: "It's not too strange when you break it down. We'll be using IVF. It'll be my sister's egg and my partner's sperm with a third-party surrogate, preferably someone who already has a family of their own.
"It's the only way my partner and I can both have a biological connection to our future children.
"It might sound vain to some people, but I think the desire to have a child with the person you love is pretty intrinsic and natural."
The couple aren't entering into the decision lightly. Samuel says a baby is still "a few years away" as the process is all very expensive, but he stresses that "it's definitely something you have to think about and plan ahead of time."
Samuel has been floating the idea with Bronte on and off for a while, but says they started speaking more seriously about it as they got older.
He said: "I think she's excited about it. We've always been close so I think it means a lot to her that she's in a position to help Brad and I start a family one day."
Bronte won't be known as the child's mother but Sam thinks he and Bradley will call her a 'special auntie' or 'fairy godmother'.