I've only ever owned feamle, and probably only will ever own females because I have a serious issue with the aesthetic appearance of certain male dog anatomy (especially the larger breeds, which is all I'll ever own)
I get soooo grossed out in class when my make pups get "excited" :o so I just couldn't ever have a male dog of my own.
Now the same anatomoy in cats is an entirely different story since its nowhere near as obvious! LOL