@article{Kohler1999, author = {Kohler, H.-P. and Rodgers, J.L. and Christensen, K.}, title= {Is Fertility Behavior in Our Genes? Findings from a Danish Twin Study}, year = {1999}, doi = {10.1111/j.1728-4457.1999.00253.x}, journal = {Population and Development Review}, volume = {25}, number = {2}, pages = {253--288}, }