translation.en: Doctor Kinsey had heard -- and there was a theory going around at the time, this being the 1940s -- that the force with which semen is thrown against the cervix was a factor in fertility.
translation.zh: 金赛博士听说过 这样一个理论，那时是40年代 精子 射入宫颈的力度 是确保生育的一大因素