Some people believe the temp of the water during spawning/hatching makes a difference.. others think the age of the female plays a role. But honestly, don't think there is any one thing a person can do to tip the scales one way or another, or to predict :(
There is a 50% chance an egg will turn out male and a 50% chance for female... Unlike fins and colour types the parents can't have "more female" or "more male" genes, it just is what it is and some spawns will have more females and some will have more males. There is no way to control it, but I think that's part of the fun!
There are a few myths on this topic
1. First 3 spawn (female) produces more males
2. Higher temp = more males
3. The very young of the pair will produce more of that gender
4. One breeder said pH influenced outcome - sorry forgot which produced what
I've read some theories that said that if the female is weaker or smaller than the male then there would be more females in the spawn and if the male is smaller or weaker than the female than there would be more males. http://bettysplendens.com/articles/p...articleid=1248
Hmm, I think I'm going to try the higher temp as a experiment. As far as weaker or stronger, my female has stronger genes than the male and I will assume h is weaker because h was from a petstore, while the female is from Chard56. I couldn't go by age though because I have no idea how old the male is.
I breed at 86-89F and I've had different results.. one of my more recent spawns has about 80% girls, whereas one 3 or 4 spawns prior had only 10% girls - same temps in breeding/fry tanks. The one with 80% females the parents were both virgins and 3 months of age. So there are myths, but you still will just never know!