Beck Laxton and Kieran Cooper were so determined to bring up young Sasha as neither a boy nor a girl that they kept his sex secret – even from family and friends.
But when he started primary school the boy's gender started to become, er, obvious, and so the mum and dad have decided to reveal all (so to speak).
Beck, 46, and partner Kieran, 44, decided on a "gender-neutral" approach to parenting in the hope it would let his "real" personality shine through.
They referred to him as "the infant" and allowed him to play only with "gender-neutral toys" in their television-free home in Sawston, Cambridgeshire.
Beck, a web editor, told the Daily Mail: "I wanted to avoid all that stereotyping.
"Stereotypes seem fundamentally stupid. Why would you want to slot people into boxes?
"It's like horoscopes. What could be stupider than thinking there are 12 types of personality that depend on when you were born? It's so idiotic.
"Gender affects what children wear and what they can play with, and that shapes the kind of person they become.
"I start to get cross with it if it skews their potential. It's not just a harmless bit of silliness, like horoscopes, it's actually harmful.
"My mother's very sporty and my dad was very emotional. We'd watch The Wizard of Oz and always start crying, whereas my mum would think we were really soppy.
"So it's always seemed obvious to me that stereotypes didn't fit the people I knew."
The couple made their decision as soon as Beck fell pregnant.
I think finding out the sex at the scan is awful. I'd ban it. It's like opening your presents before Christmas.
"I worry that people start making all these presumptions about what the child's going to be like.
"I was a bit curious after the birth of Sasha, but I wanted to make sure that I wasn't making any assumptions myself. So we just sat there, a bit zonked, just gazing at Sash, and at each other.
"When we didn't reveal his sex to the family there were a couple of people who assumed it was a boy, because that's the default: something's male unless you say it isn't."
Over the past five years the couple have become skilled at evading the question and have simply referred to their son as "the infant".
"In the mother and baby group I was the last person to introduce myself and I said 'I'm Beck, and this is Sasha'," said Beck.
"And of course somebody said straight away: 'So is it a boy or a girl?' I said, 'I'm not going to tell you.
I discovered later that I'd been described as 'that loony woman who doesn't know whether her baby is a boy or a girl'.
"And I could never persuade anyone in the group to come round for coffee. They just thought I was mental.
"I don't think I'd do it if I thought it was going to make him unhappy, but at the moment he's not really bothered either way. We haven't had any difficult scenarios yet.
"Nobody's ever mentioned it and I would hope that if they actually said something to Sasha, he'd be confident enough to make a good response."
Sasha has worn both girls' and boys' clothes for the past five years. He has chosen to wear a blouse from the girls' uniform list to school. He wears a blouse with ruched-sleeves and a scalloped collar to school from the girls' uniform list, and has been banned from sporting combat trousers. He is also encouraged to wear flowery tops at weekends.
"I just want him to fulfil his potential, and I wouldn't push him in any direction," said Beck.
"As long as he has good relationships and good friends, then nothing else matters does it?
"All I want to do is make people think a bit."
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