One question that comes up for almost any prospective pet owner, is whether they should get a male or a female. Of course,
neither sex is universally better but, depending on what you want or what you can deal with, it's usually better to have one
or the other (for obvious reasons, unless neutering/spading is an option, males and females shouldn't be kept together).
With mice, males and females have quite a few differences. Males tend to be bigger, and a little bit harder to lose,
while females are small and active. If you want a mouse that is willing to run around and play a lot, usually a female is more
along the lines of the pet you want. On the other hand, if you want a mouse that'll be pretty cool and laid back, while
still being playfull at times, maybe you'd want a male mouse.
Appearance-wise, females seem to be more sleek and agile looking, while males look a little more lumbering. Some people
also might not like the look of the male's genitals, but after a day or so, they are barely noticeable at all.
Males are a bit more musky than females are, meaning that if you don't want to clean out the cage that often, then you
might not want a male.
Females, on the other hand, are more prone to mammary tumors if they're not spaded, much like female pet rats.
If you want just a single mouse, a male mouse might be the choice for you, because they don't house well with other males.
If you want multiple mice in the same cage, you would definitely need females.
Either way, a mouse is a pretty good pet choice and I would definitely suggest adopting one, whether it be male or female.