We examine the assortative mating patterns of new parents who are married, cohabiting, romantically involved and no longer romantically involved. Using data from the Fragile Families and Child Wellbeing study, we find that relationship status at the time of a birth depends mainly on father's race rather than on whether mother and father's race/ethnicity differ. Crossing race/ethnic lines does not appear to have much effect on relationship transitions following a birth. Rather, parents are less likely to marry after a birth if one parent is black, and the relationships of Hispanic couples are particularly stable. Crossing educational lines has little effect on relationship status at birth, but same-education couples had a slightly lower risk of divorce following the birth. A table of Coefficients from Multinomial Logistic Regression of Parents' Relationship Status at Birth on Parents' Race, Education and Control Variables is appended. (Contains 3 tables, 2 figures, and 2 notes.)