Female
orgasm presents a number of biological puzzles. Heated debate surrounds whether
it is an adaptation that contributes to fitness or a by-product of
other—male--adaptations. Female sexual response variability has not been
incorporated into the debate. We investigated a range of key features of
response variability and linked these to partner characteristics. There is
support for a key feature of female orgasm--that may contribute to fitness--worthy
of further investigation. Current research is focusing on a novel method of
investigating sperm back flow. This may well help to settle questions of mate
choice versus sire choice models of the function of human female orgasm.