All dogs are boys and all cats are girls. Just ask Troy!
Tigers especially raikou look more masculine imo. Lions with manes such as entei are definatley masculine,fact. Suicune is a more feminine cat though.
What I'm saying is that it's silly to apply our notions of gender on Pokemon since they're animals. Most would say that most dogs are masculine-looking and cats feminine-looking, but obviously there are female dogs and male cats.
Consider that foxes are considered a symbol of femininity in Japan and that there are still male Ninetales and soon male Fennekin, because foxes are male as well. I just think these sort of topics are quite silly.