We know that rats grow OK in orbital microgravity. Doesn't seem like strong gravity is required for mammalian morphogenesis to work. "As we reported previously

We know that rats grow OK in orbital microgravity. Doesn't seem like strong gravity is required for mammalian morphogenesis to work. "As we reported previously (Ronca & Alberts, 2002b), pre- and postflight body weights of dams and the body weights of the offspring used in these experiments were comparable across treatment groups. Within 48-72 hrs following landing, the rat dams that contributed offspring to the postnatal studies gave birth to healthy offspring." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2610337/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2610337/