ABSTRACT

A peak in coital behavior around ovulation in the female is a consistent finding across most mammalian species. Luteinizing hormone (LH) surge onset appears to be a biologically meaningful reference point from which to organize human coital behavior across the female’s menstrual cycle. Cycle length was chosen because of the positive association between cycle length and follicular phase length and because it is simple, inexpensive, and noninvasive to collect. The validity of the nonhormonal estimate was tested on a sample for which urinary LH, cycle length, and coital behavior were available. Coital behavior in human couples has been found to peak on the LH surge onset day at midcycle. LH surge onset day thus appears to be a biologically meaningful reference point from which to explore changes in human behavior across the female menstrual cycle.