On the International Space Station several generations of mice should be brought through full gestation in a centrifuge simulating Martian gravity.
This experiment will provide data on how mammalian health is affected by long-term exposure to lower levels of gravity, focusing on bone loss, changes in bone structure, muscle atrophy, affects in the inner ear, and child-bearing off-Earth. The results from the experiment would be compared against a variety of earth based controls, including vivarium, hindlimb suspension, partial weight suspension, flight habitat effects, and short-radius centrifuge testing.
Data will further our understanding of osteoporosis, neurological disorders, fetal development, and more - on Earth and space exploration in general.