Here you numbers nuts. This is a mixture of the age old correlation vs. causation argument, as well as a little fun with statistics.

With the exclusion of the WNBA, because it's boring. A statistically significant number of athletes of national league level sports have both the X and the Y chromosomes. The statistic exceeds 51%. It also exceeds 99% but that is neither here nor there.

Now is this true because those people with both have an increased opportunity to gain placement on a sports team competing at a national level (cum hoc ergo propter hoc)? Or is it possible that the presence of both varieties of this genetic material are what make these athletes perform at such a high level in the first place (post hoc ergo propter hoc)?

Who knows? It's just science. And by science's very nature, it cannot be understood through the use of statistics, an appeal to the scientific process, or through an examination of various logical fallacies.

You all have a good day. Go Tamika Catchings, score all the points!