Tax Prof Shari Motro (Richmond; Visiting Georgetown) has published The Price of Pleasure, 104 Nw. U. L. Rev. 917 (2010). Here is the abstract:

Condoms break. Diaphragms malfunction. Even hormonal contraceptives aren’t 100% effective. Three million American women become pregnant unintentionally every year, and the rate of unintended pregnancies is especially high among young unmarried women. What is the legal relationship between these women and the men with whom they conceive? Current law treats unmarried lovers as strangers, leaving women to bear most of the costs of “free love” on their own. This Article argues that a different default should apply. Unmarried lovers who become pregnant are neither spouses nor complete strangers; they are something in between. Sex creates a unique type of relationship, and sex that results in pregnancy extends this relationship. Unless the parties agree on a no-strings-attached rule, the law should reflect this reality regardless of whether the pregnancy ends in abortion, miscarriage, or childbirth.