My ex-wife is denying me overnights with my newborn child because she's breastfeeding. Can she do this?
In the majority of cases, breastfeeding is not a legitimate excuse to deny visitation or overnights with the child. If it becomes an issue, the mother's milk could be pumped and saved for use during the overnight period, or the infant could be fed formula if necessary.
This information is also covered in the article, Countering The 'Breastfeeding Argument'.