Pregnancy or Motherhood Cost? A Comparison of the Child Penalty for Adopting and Biological Parents

This study investigates whether the high labour market costs of having children for women can be explained by the associated biological costs. Estimating the significance of biological factors requires separating the effects of having a child from the effects of giving birth to a child. This separation is estimated by comparing child penalties between biological and adopting families. Adopting mothers neither go through pregnancy nor nursing, thus lessening the burden of the sex-specific costs of having children. I apply an event study by following parents over 16 years and find large and significant child penalties for all mothers although the penalties are slightly smaller for adopting mothers than those for biological mothers. Neither adopting nor biological fathers experience any child penalties. The results suggest that child penalties have some biological components, but the burden is on women regardless of whether they carry the biological costs related to pregnancy.