In my first round of breeding Crested Geckos there was one singular thing I never really got a clear consensus on in reguards to breeding them…
It’s the topic of whether incubating CG eggs in certain temperatures determines the sex of the gecko, like Leopard Geckos.
My experience of the past was always this: I incubated all of my CG eggs at room temp for my area which is ~74-75°F pretty much year-round. I got both males and females that hatched, but a majority of them were male… I had talked about this to a few CG breeders at expos and I always got mixed responses, some saying it was my incubation temps and others were saying its just 50/50 chance and that my majority hatchlings being males was just luck.
I want to know the thoughts, research or experience of those of you here who breed CGs on this topic.
Old silly CG pic for flare 
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From my understanding…
There’s no true way to determine it by temp. There’s been some trends noted that seem like they’re TSD… but they’re not as accurate as in leopard geckos. A low temp in leos means pretty much all females. High temps are mostly males with the exception of the ‘hot females’ which can have some behavior and reproductive issues.
With cresties the numbers are pretty even, and temps only change the ratio a little bit. As an example let’s say 3:7 and 7:3. If you incubate at low temps, while you may see more females in the ratio males will still occur. The opposite happens with higher temps and more males than females happen. So you can’t really gamble on something like that. 
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There’s never been any meaningful evidence to suggest it’s a thing. Some people have said they’ve seen a slight increase in females hatched at lower temps, and males at higher temps, but we’re talking a 55/45 ratio or something like that, pretty statistically insignificant. Most people nowadays incubate them at very low temps since they believe longer hatch-times = larger, stronger babies, and they they still end up with both males and females. Except for my very first clutch, ive always incubated at room temp (74-82) and gotten a mix, with a slight preference for females actually. My very first clutch ever was incubated at lower temps for the first while (~71f, until my incubator decided to die on me) and i got 1 male and 1 female
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