The few males we hatched this year, plus all of the young males we received definitely grew slower than the females for us. The shipping and new home may have created a little speed bump in some cases. We did have a few males that grew just as fast as the females, but the majority grew a little slower. It may have to do with the particular morph as well, but I still say simply every gecko grows at a different rate. I may be a little sided too since 95% of what we hatched was females.
I would definatly say our females grow slow as snails. We have two young-adult geckos, that have been like that, for like 2 months all ready, and not grown more than half an inch at most, and still LOOK like young geckos. We've also had an unsexed baby for a month, but thats not too long, and s/he is definatly getting WIDER.
I have not really noticed any difference in the growth rates of males vs. females overall. Each gecko develops at their own pace... but it's usually the ones with the best appetites that grow fastest, lol!
I agree with Marcia, the growth rate really just depends on their appetites. I have some females that would eat until they explode if I would let them. And I have some that eat only once a week at times. Although I must say my fastest grower that I have had was my male Vincent who I hatched here at home. He was about 8 months old and 71 grams. I say he has the growth record.