Colin Manning

Sex with 21 Women Lowers Risk of Prostate Cancer I saw this story reported today and it stuck me as particularly poor science. As click bait, it is irresistible. It has it all: sex, cancer, an excuse to use the word ejaculation and the conclusion that promiscuity is better than monogamy, unless you're gay. The study found that men who had slept with more than 20 women had significantly lower instances of prostate cancer than those men who slept with less. I have no reason to doubt the numbers.  But many reports of the findings illustrate the classic fallacy of confusing correlation with causation.  I have noticed that on on days when lots of people carry umbrellas, the buses are much fuller.  But it would be wrong to jump to the conclusion that umbrellas cause busses to fill up, and that increasing the  number of umbrellas on our streets would improve bus company revenues.  It is similarly incorrect to conclude that the full busses cause people to c...