We examine resource allocation in step-households in the United States and
South Africa to test whether child investments vary according to economic a
nd genetic bonds between parent and child. In the United States, households
spend less on food when a child is raised by a nonbiological mother. The r
eduction is identical for step, adoptive, and foster households, consistent
with the hypothesis that genetic ties are the ones that binds. In South Af
rica, where food spending can be disaggregated, households spend less on mi
lk, fruit and vegetables, and more on tobacco and alcohol, in the absence o
f a child's birth mother.