I like boy dogs.
Just a personal preference. Funnily enough, all the dogs that I dogsit are boys and only ONE of them lift their leg at all. Boston Terrier mix, two Goldens, one Rottweiler, one Lab, two Boxers, and a few others at some point that I've watched. One of the Boxers lifts his leg to pee (but not "mark") and that it!! LOL. It's so funny to have all these males that squat. All are neutered. Jackson was neutered at 7 months-ish and he still squats to pee but he will lift his leg outside at parks and stuff but never indoors. I just have better connections with boy dogs for some reason- grew up with females though, maybe that's why I prefer boys now?? But yeah, I think it's good to have 1 of each in general. Two females may fight, may not, but I think you lower the risk getting the opposite sex.