When my daughters were younger I made friends with another mum at swimming lessons. Her kids, two boys, were around the same age as mine, so we easily fell into poolside small talk. Week after week we sat chatting about the trivia and relentlessness of mothering. And then, one Tuesday, out of the blue, she made a confession; she was jealous of me, I was living the life she had always dreamed of. I had daughters.
Mothering girls, my new friend told me with a sigh, was much nicer than mothering boys. Girls happily sat still with a colouring book or doll. They didn't ruin their clothes, climb on the furniture or play with their genitals. "You're so lucky," she said sadly.
I told my new friend that she was woefully misinformed. Perhaps some girls were like that. But so were some boys. Playing with dolls and colouring in isn't hardwired in female DNA. Likewise, playing with sticks and laughing at farts isn't a prerequisite for being male. I should know - my daughters were every bit as boisterous as her sons. They played with sticks and rocks, made mud pies, climbed trees and despite not having a penis, possessed a healthy curiosity about their genitals ("the dinner table is for eating, not for playing with your vagina").
The girl myth persisted. My friend believed that had she given birth to daughters, rather than sons, her life would be complete. If she could have chosen girls, she would have done. In her case it was academic; her sons were conceived naturally and their sex and other genetic characteristics were left to chance. But thanks to IVF, sex selection is not only possible; it is practiced legally in countries such as the United States, Mexico, Italy and Thailand.
It might seem harmless, but the assumptions that underpin sex selection are the same assumptions that underpin sexism and gender inequality.
Last week the National Health and Medical Research Council (NHMRC) released its revised national guidelines for IVF clinics, which maintained a ban on sex selection for non-medical reasons. This means that in Australia parents can only select the sex of their embryo in order to prevent the transmission of a serious genetic condition. But there are other reasons parents want to select the sex of their baby.
Parents that already have children of one sex might be keen to guarantee the sex of a new addition to achieve "gender balancing" – we all know a couple that kept trying for a son, and ended up with five girls (or vice versa). But behind the desire to "gender balance" there is a lingering misconception that parenting girls and boys is an inherently different experience.
This misconception has many consequences, as bioethicist Dr Tamara Kayali Browne, a lecturer in health ethics and professionalism in Deakin University's School of Medicine has discovered. Dr Browne has conducted extensive research in the field of sex and gender. She tells me that allowing parents to select their child's sex perpetuates harmful gender stereotypes and places false constraints on parent-child relationships.
Dr Browne's research, which focused on parents in Western countries, found that the most common reason for sex selection was a desire for a certain type of bond or parenting experience. "Mothers will say that they want a girl because they want to have a strong mother/daughter bond. Or that they want a girl so they can play dolls with her or braid her hair," she says.
Likewise, some fathers say they want to have a boy so that they can play sport together or go fishing. But Dr Browne says that these ideas actually come from long held gender stereotypes and have little to do with sex.
"As far as we know, there is no biological reason why you can't enjoy the kind of bond or experience you want with a child of any sex. So what that means is that sex selection is unnecessary, it reinforces assumptions about gender that are unfounded and harmful," she explains.
Gender stereotyping has stark consequences - the assumptions that parents make about their new baby can inform the relationship that they have with them. "The mothers who want a daughter because they really want to experience a strong mother/daughter bond feel that they cant have that close bond with their son.
"Not only are they depriving their sons of a close relationship with their mothers, but they are also depriving themselves of a close bond with their son," says Dr Browne.
On top of this, those same assumptions can have a big impact on the way that a child develops. "Babies and children are like sponges, they learn very quickly from their environment. They will respond to cues you give about certain types of behaviour," Dr Browne tells me.
This is evident everywhere from gendered toy aisles in department stores to gendered clothing. My eldest daughter preferred the motorbike and dinosaur T-shirts in the boys section until she was old enough to read the "boys" sign – the day she realised that she was "supposed" to prefer the bunnies and kittens was very sad for both of us. I told her it didn't matter, she told me she didn't want her friends to laugh.
There is another consequence and it's much broader than the dynamics of individual families. Perpetuating gender stereotypes via sex selection reinforces the idea that men and women are infinitely different.
Sex selection might seem like the answer for parents desperate for a girl or boy, but choosing one set of genitalia isn't the same as choosing gender - especially when you consider the possibility that a child may be transgender or otherwise gender-nonconforming.
It certainly doesn't guarantee a set of characteristics, personality traits, likes or dislikes. It might seem harmless, but the assumptions that underpin sex selection are the same assumptions that underpin sexism and gender inequality.
"What's the difference between saying boys should play with cars and girls should play with dolls and saying men should be out in the workforce and women should stay at home?" asks Dr Browne. "It is hypocritical of us to enforce ridged gender stereotypes on children but not on adults."
In other words, sex selection supports the idea that men and women should be kept in their place. And there's nothing harmless about that.