The best dog I've ever had was a beautiful male sheltie/briard mix (looked like a light blond golden retriever with sheltie ears). He was sweet, loyal, loving, gentle, could be both energetic and calm, and was extremely smart. He could also be very stubborn at times, but that was a little more the briard than the sheltie in him.
My current male sheltie (9), while smart, and sweet to us (and has become more affectionate with age), is neurotic when it comes to people who visit our house. He barks and paces, and backs away from them. It takes forever for him to get used to them. He also barks at other animals he sees (as long as he's protected by a door, fence, or car - open them up and he's a coward). If we take him somewhere like the vet, he's a complete angel once he's inside, lol. It's basically something he does on his own territory. We got him as a puppy, like all our other dogs, but he was from a BYB (didn't know any better at the time) and my guess is genetics factor into some of his problems. He's very docile otherwise and sleeps/rests most of the day, only getting up every once in a while to "protect" the house or the yard from "intruders", lol.
I also have had three females - a sweet-to-humans/feisty-to-other-animals rescue terrier mix (but that's mostly a breed trait), and two very sweet, smart, energetic/playful shelties. My youngest (now 8 months) is less skittish around other people, but she's also got a little more spunk and very little sense of fear when it comes to canine personal boundaries, lol. She also loves to snuggle. My oldest female (4) is the sweetest girl ever (and the best greeter to her family) and given the chance, will eventually warm up to visitors and be very friendly. She loves to be petted, but isn't much of a snuggler. They both sleep on my bed at night.
I guess I think it all depends on the breed, lineage, upbringing, and personality of the dog. If they come from a good breeder and a good heritage (personality/temperament-wise), then I don't think it matters which gender you choose. They both can be great. My advice would be to pay close attention to the parents' temperament/personalities. They are what will give you an indicator of what the puppies will be like. Just my two cents.
