It's big enough to show fairly significant sex differences for a preliminary study, or I doubt politically correct Nature would have published it. Since the study was done at University College London, a country of socialized medicine and a hurting health system, I'd be surprised if they could afford a sample that was much larger. When I had a simple CT of the abdomen and pelvis, I was charged US$ 1070.
A study with only 32 subjects is statistically worthless.