1. Science is not something to be "believed" in. It is a method of determining facts based on observation and repeated experiment.

2. Evolution is a fact. The theory of evolution as proposed by science to explain that fact is as thoroughly proven as anything can be (such as the sun being the center of the solar system, uniform acceleration due to gravity in general circumstances, etc.)

3. Sexual identity issues are recognized by science as existing, in the form of (a) people born as hermaphrodites and given corrective surgery to "choose" one sex or the other and (b) people whose neural wiring in their brains leads to a condition where psychological sex and physical sex are not identical.

4. Even after having stated these points, virtually no one is an adherent of scientism, the notion that science explains everything, like the nature of romantic love, why my favorite color is green, what thoughts really are, why matter and energy even exist or why I chose to eat at a Chinese restaurant rather than an Italian one the other day.

You're entitled to your own absurd opinion on the Creation, even though Creationism is a relatively new notion and early Church Fathers didn't even take it to be a literal explanation of creation. You're entitled to judge everything by an irrational standard (thereby once again shitcanning the notion of scientism). To the extent someone is a blind adherent of scientism (which is taking science out of the realm of science and into the realm of belief) then we should all laugh at that person. However, most people who "adhere to science" do not adhere to scientism, so on the basis of points (3) and (4) Jenner is perfectly capable of doing whatever she wants to. Judge not, lest ye be judged. We'll all see what happens after we die, unless there is nothing after we die, in which case we won't. Either way, there's nothing to be gained by bitching about Jenner's life choices. They're hers to make, not yours.