Hm. I've had a lot of rats, so here's some stuff you might want to know:
1) Rats are very social. If you're getting one, you should put serious thought into getting another same-sex rat to keep it company unless you're willing to spend a lot of time with it.
2) There's actually a lot of difference between owning a male and female rat. Females tend to be smaller and cleaner and more energetic and curious. Males are bigger, have oily fur, and tend to be more calm. A male will fall asleep on your shoulder, a female will do laps around your shoulders and explore your hair. Both will pee on you a lot.
3) As long as they're well-socialized they will probably never bite, unless you get in the habit of sticking food through the bars of their cage. They'll start snapping at anything coming through the bars if you do that.
4) Chances are they're going to end up with health problems within a few years. Domestic rats are extremely prone to respiratory disasters and (females especially) cancer. I had three of mine end up with perpetually-growing tumors. Also note that certain strains of lab rats have been purposefully bred to be predisposed to certain health problems.
5) Make sure the
cage and bedding is suitable. Avoid cages with wire bottoms or shelves and stay away from cedar and pine-based litter. Also, make sure to give them plenty of safe stuff to chew on.
Sorry if you already knew any of this.