(No) Babies without Sex? Exploring the Link between Couples’ Sexual Frequency and Parity

Natalie Nitsche, Australian National University
Judith C. Koops, Netherlands Interdisciplinary Demographic Institute (NIDI)-KNAW/University Of Groningen

Humans, like all mammals, reproduce sexually. Sexual intercourse is thus necessary for human reproduction. The biomedical sciences document significant linkages between sexual intercourse frequency and various aspects of human fertility. Yet, there is a surprising paucity of studies on systematic linkages between human sexual activity and fertility in demography. This study sets out to address this gap. It examines the association between couples’ sexual frequency, their current parity, and their transition to first birth using data from the German Panel Analysis of Intimate Relationships and Family Dynamics. Results show that sexual frequency and fertility are associated in meaningful ways. First, we find a curvilinear association between couples’ current parity and their sexual frequency. Sexual frequency drops after the first birth, remains lower at parities two and three, but is significantly higher among couples with four or more children. However, higher sexual frequency among higher parity parents appears to be rooted in unobserved heterogeneity, indicating that couples who have four or more children may be selected on factors linked with both their higher fertility and sexual frequency. Second, we find a positive association between sexual frequency and time to conception, but only among couples who are unsure about their fertility intentions.

Keywords: Fertility, Sexual and Reproductive Health and Rights, Family Planning and Contraception, Longitudinal studies

See extended abstract.