Book Chapter
Genetic influences on fertility behavior: findings from a Danish twin study
Kohler, H.-P., Christensen, K.
In: Rodgers, J. C., Rowe, D. C., Miller, W. B. (Eds.): Genetic influences on fertility and sexuality, 67–84
Dordrecht, Kluwer Academic Press (2000)
Abstract
Whereas most research focuses on how variations in socioeconomic conditions contribute to the diversity in fertility behavior within a population, this paper analyzes the fertility of Danish twins in order to find possible genetic influences on an individual´s fertility decisions. The analyses reveal that male monozygotic twins have a significantly higher correlation of completed fertility than their dizygotic counterparts, which suggests a (dominant) genetic influence on male fertility behavior. For females, an important gene-environment interaction emerges: the difference in the correlation of completed fertility between mono- and dizygotic twins changes over time. Only for later cohorts is there evidence for a greater similarity of completed fertility among female monozygotic twins as compared to dizygotic twins. This means that the genetic influence on the fertility of females increases over the sample period. (AUTHORS)