The concept of GNC children being statistically likely to grow up to be gay (especially boys) is usually referred to as ‘pregay’ or ‘protohomosexual’ in research papers. There is a lot of it about besides Bailey and Zucker.
Of course, much of the discipline of ‘sexology’ is, in hindsight, really fucking circumspect so simply linking to papers online is a bit like playing academic Russian roulette, we’re quite likely to find a paedo apologist/queer theorist lurking in the chamber.
Add in the fact that statistically confirming parents homophobic fears about their GNC child growing up to be same sex attracted is (was?) unlikely to contribute to better outcomes for those children and it’s a bit of a quagmire.
I like to think that nowadays it would be more ‘Don’t worry about any unusual GNC behaviour, your child is statistically likely to grow up homosexual!’ and that being a relief and a comfort to parents, rather than the ‘Oh shit, your child will be a homosexual if you don’t pray hard/beat them/take their toys away’ it might’ve been historically (but I realise that outside of my Atheist, feminist, artsy social circle it can still be very hard for GNC maybe-gay-one-day kids, especially those growing up in orthodox/conservative religions).
GNC children who grow up to be gay do not necessarily retain their gender nonconformity in adulthood btw.
Lots of very macho gay men were once swishy, sparkly little boys!
Feels weird to generalise this because we’ve seen such massive shifts in terms of childhood conformity to sex stereotypes over the last 40 years (and children growing up with feminist mums have been somewhat sheltered from pressure to gender conform at home, whilst still being steeped in media/advertising pressure and peer pressure at school) still…
Girls generally have a wider spectrum of societally acceptable gendered behaviour available to them in childhood than boys do but girls tend to get those GNC behaviours squashed out of them hard and with little warning at puberty (one of many reasons why puberty can be particularly hard on ASD girls who don’t cope well the sudden ‘rule change‘) whereas GNC boys have a more consistent level of societal disapproval all the way from preschool to young adulthood (especially from hetero adult males, eg Dad, which is sometimes enforced by adult females eg Mum, even if the original disapproval didn’t come from mum and from male peers at school).
(following this post up with a few links but dare not click away to find them in case this gets accidentally deleted 🤣)