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.
Доктор Кинси слыхал, а в те времена, в сороковые годы, была в ходу такая теория, что сила, с которой семя извергается в матку, влияет на плодовитость.