Lab mice are critical to science. They are used as a way to test out new drugs and to carry out other scientific tests in order to ensure the safety for humans. Although those sticking up for animal rights may not approve of the use of lab mice, they have saved the lives of millions of people and have helped develop medicines that are for the greater good.
One thing however that is imperfect about testing with lab mice is that they're typically always male. Most of the time, female lab mice are left out of testing. It's thought that female hormonal changes, which can through testing out of whack, make it harder for scientists to get a clear understanding of their research.
On the other hand, when looked at more closely, it's easy to see how this can be a problem for humans. Since males and females have very different bodies that work in different ways, something that works well for a male may not work as well for a female or vice-versa. A smaller dosage may even be required for a female than a male, which is hard to tell when only male lab mice are being used.
Even in the science field, it's important to get some gender equality rolling to kick-start scientific research in the right direction.