This study examined short- and longer-term sequelae of parents' prenatal expectations of their future family process, and traced subsequent stability in coparenting solidarity from infancy through the toddler years. One hundred and ten couples expecting a first child participated in prenatal assessments of coparenting expectations and differences, and in 3-month post-partum evaluations. Forty-five couples completed subsequent assessments at 12 and 30 months. At each time point multi-method evaluations of coparental adjustment were obtained. Men's and women's expectancies during the pregnancy and the degree of difference between their self-reported beliefs about parenting predicted post-baby coparental adjustment, with latent class analyses suggesting aftereffects of prenatal expectancies up through 30 months for some couples. Coparental solidarity was also stable from 3 to 12 and from 12 to 30 months. Data indicate that the lens parents bring to bear on their emerging family system is not immaterial, and that early-emerging coparenting dynamics portend longer term coparenting adjustment.