In sport the sexes are separate. Women and men do not run or swim in the same races. Women are less strong than men. That at least is what people say. Women are called "the weaker sex", or, if men want to please them, "the fair sex". But boys and girls are taught together at schools and universities. There are women who are famous Prime Minister, scientists and writers. And women live longer than men. A European woman can expect to live until the age of 74, a man only until he is 68. Are women’s bodies really weaker
The fastest men can run a mile in under 4 minutes. The best women need 4.5 minutes. Women’s time are always slower than men’s, nut some facts are a surprise. Some of the fastest women swimmers today are teenager girls. One of them swam 400 meters in 4 minutes 21.2 seconds when she was only 16. The first "Tarzan" in films was an Olympic swimmer, Johnny Weissmuller. His fastest 400 meters was 4 minutes 59.1 seconds, which is 37.9 seconds slower than a girl 50 years later This doesn’t mean that women are caching men up. Conditions are very different now, and sport is much more serious. It is also so serious that some women athletes are given hormone injections. At the Olympics a doctor has to check whether the women athletes are really women or not. It seems sad that sport has such problems. Life can be very complicated when there are two separate sexes !
 

in this passage the writer wants to tell us that（）