Chronotype impact on mating, desire for sex and sexual activity in humans.

Research on assortative mating by chronotype in previous years has yielded contradictory results. The aim of the study was to examine whether non-cohabiting partners in short-term relationships shared the same chronotype. A sample of 100 heterosexual couples completed the Composite Scale of Morningness (CSM) questionnaire and responded to additional questions. No evidence of assortative mating for chronotype was found, but there was a significant positive correlation between male and female time of waking up, time of greatest desire for sex and actual time of sexual activity. Additionally, female chronotype was significantly associated with the timing of peak sexual desire. Morning-type women declared the greatest desire for sex at 15:00-18:00 more frequently than evening-types. In case of actual sexual activity, men and women declared 21:00-00:00 most often, regardless of chronotype. It is likely that adapting to social schedules aligns activity timing across different chronotypes. They are performing their activities during which they get to know each other at similar times. While chronotype may not be critical in initiating relationships, it could influence the maintenance of long-term relationship satisfaction.