Mother's roles in conception, gestation, birth, and parental rights are becoming marginalized with the help of new reproductive technologies and surrogacy arrangements. A woman's role as mother has historically been based on gestation and birth of children. New reproductive technologies and surrogacy introduce a new emphasis into gestation and birth, a heightened emphasis on medical control of conception, gestation, and birth, and an orientation toward the woman as a mere "vessel" or "container" for the fetal patient. Changes brought by these reproductive arrangements pressure legal systems to refine definitions of motherhood and the expected behavior of pregnant women. These tendencies will probably increase as the technologies develop. © 1991.