Yevamot 42: Tracking the 7- and 9-Month Babies

Two scientific points of interest - the 7 or 9 month baby, suggesting 1 month wait is all that is needed to determine paternity, not 3 months. What are the implications of these assessments? Including the woman's incentive to lie. And a deeper dive into the 7/9 months. Plus, pregnancy while nursing. Also, following some of the halakhic guidelines to determine the rulings of the Tannaitic literature, including or specifically, when there's a machloket.