When male mice and pregnant or lactating female mice are placed closely together ... Females were not used routinely in research, he writes, as the ovarian cycle was supposed to change several ...

so many of the female mice are pregnant. They also believe the man still has around 400 mice at his home. Some of the mice are available for adoption today. For more information, visit this link.

After giving the mice a mating period of a few hours, the scientists then removed the female mice and waited to see which of them got pregnant. In the control group, 30 percent of the females ended up ...