For egg layers, corydoras are pretty easy to breed. I've had good luck with them. They were the first egg layers I was ever able to breed and raise.
I have 5 bronze corys that seem to produce eggs every few weeks--way too many for me to try to raise. And I also have 9 pandas that I am raising to breed. I can't wait for them to get old enough!!!
To tell the male from the female you pretty much have to have both and compare them. The female will be larger and wider than the male. The male will also have a more pointed ventral fin than the female but I have never been able to tell this way because either the fish are moving too much or they're sitting on them.
When cory cats breed they like to do it in a group even if it is only one pair that are actually breeding. This means that if you get 4-6 fish you will not have to worry about telling them apart. You will almost certainly get some of each.
Most corys will not eat the eggs if the eggs are healthy, but there are always exceptions. Usually they will take care of them, inspecting them and removing any that may have spoiled to keep the others safe.
How many cory cats do you have and what tanks? Will you have to get additional equipment/fish?
