I'm a daddy, leopard geckos just hatched!! (DUW!!)

Well, I have two stores on the line for a few, I also have some local people who want some, so that isn't really a problem. Leopard geckos are very popular. To anyone thinking of breeding anything though, you need to be prepared to deal with the young for a while if miscarry. Because you never know, and it does become your responsibility. I won't get on my soapbox

The first I ever heard of sex in reptiles being temperature determined was american alligator eggs back when they were listed as threatened & endangered. I don't know the exact science, if I remember correctly it has something to do with the fact that physically all animals start off as female, and the increased temps encourage the male development more. Someone may have better info on that. It is actually similar with all reptile eggs, though not always as simple. With Leos, if you incubate at 88-89 you are all but guaranteed males, 81-82 you are all but guaranteed females. Other species it is not as exact, just increases the odds, and some are trickier to hatch successfully, and the animals may be worth quite a bit more money, especially for a professional breeder, so they shoot for the "safest" temperature. This is generally more common with lizards, but there is an effect on snakes as well. It does vary quite a bit though.

I have a large homemade rack, heated with flexwatt heat tape and a thermostat, I use to keep a number of animals in. I used a tub in that with the eggs in individual containers with the moist substrate for humidity. I can't keep exact temps, and have to take the temperatures of the animals into account, which is really more important. But the leo eggs are quite easy and forgiving so it works. I know people that just put the eggs in small containers with moist substrate, and put them on a top shelf of a warm closet.