Females tend to be more dominant than males, so households with all males and one female, or all males tend to get along better than having multiple females. HOWEVER, some may beg to differ. I am in a household with four females and one male. Ones a chi and she pretty much keeps to herself but is VERY, VERY food aggressive. The second youngest is a female ACD who is VERY aggressive towards other dogs but overly submissive to people. Then there are Charlie and Jamie, who are pretty mellow and don't cause any conflict whatsoever. At the top of the chain is dear old Hannah, she's like the wise old lady who looks over the flock and keeps things under control.

So in experiences with my situation, the lower end females tend to be more aggressive with the other dogs. This could also be because Angel (the ACD) was never properly socialized, and Chiquita (the chi) is pretty much a lap dog with no training other than being housebroken. The three trained dogs get along beautifully though.