The bulk of evolutionary theory is based on "morphology", the study of physical forms. For extinct species, it is the only basis.
DNA analysis tells us what is really going on inside a living organism (whether or not we assume common descent).
So what happens when DNA analysis overturns an entire branch of the "evolutionary tree"?
"With this study, we learned two major things. First, appearances can be deceiving. Birds that look or act similar are not necessarily related. Second, much of bird classification and conventional wisdom on the evolutionary relationships of birds is wrong."(Note that this analysis is based on comparison of just 8,000 bits of DNA)
Similar mistakes are made on the human scale. Some people attempt to justify casual sex through an appeal to biology. A recent article notes:
"Indeed, during the ovulatory phase (between days 10 to 18 of their cycle), women report increased sexual desire and arousal, with a preference for short-term partners."When biology informs us what is right and wrong, we get "If it feels right, just do it" (Ironically, many who call themselves Christians believe the same thing, and blame it on the Holy Spirit).
"It seemed obvious that if our female ancestors really were adapted to short–term relationships they ought to enjoy them, just like men do."Of course, when biology then makes us feel guilty...
"Overall women’s feelings were more negative than men’s. Eighty per cent of men had overall positive feelings about the experience compared to 54 per cent of women."It's evolution! The title of the article, "Women Have Not Adapted To Casual Sex". (Note, this is not a reference to recent "adaptation", but long term "evolutionary" adaptation).