I have a brother and sister, same litter, 2 yrs old. His nails need clipping once every two months, hers minimum every two weeks. His are perfect show dog trim, no resistance at all. Hers are long, she is resistance, and i cant get them anywhere near as short as his without nicking the quick. They both are great lovers of philly cheese and ir makes it much easier for us to smear some where she can reach without squirming. He just sits and lets me do it. Been doing this for 30 yrs. but i have never seen nails grow as quickly as hers. I have been told the difference is hormones...?
We have a 3 year old girl who grows nails at an astounding rate. You can have them short enough that you don't hear the click in the morning and by the evening it's "click click click". That's the fastest growth we've ever seen from a male or a female, so I'm going with individual variation rather than hormones. That doesn't mean there isn't a sex variation, just that based on a small sample I haven't seen it.