All the science news sites gave headline space to a "study" purporting to show that women prefer larger penises, which therefore explains, through sexual selection, why we evolved larger penises than chimps.
Let's start with the sample used to make this sweeping statement about human evolution: 105 Australian women in their 20s. Who are, I suppose, a valid sample of humanity because the researchers had access to them.
The researchers' own data showed that the main factors influencing how attractive the women found the male images were height and shoulder-to-waist ratio, with penis size much less important. They also used fuzzy images without faces, and other "studies" have shown that a handsome face ("symmetrical" in the currently faddish evolutionary lingo) is more important to women than anything about bodies.
This study demonstrates exactly nothing about female sexual behavior. It is an interesting fact that human men have bigger penises than they need, and maybe this does have something to do with sexual selection. But it could equally be a byproduct of hormonal changes that took place for other reasons, like to promote aggression, and this scientific farce says nothing about that one way or the other.
There are few things more irritating than sexy pseudoscience. Grrrr.