I bought a couple of these for both my sons (Ages 26 and 14) and my daughter (Age 13).
They fit well on both sexes. All three of these kids wear a Men's Large in Tee Shirts, and they're all of thin-average weight. So, the shirts fit exactly as I would expect... Pretty true to size. They are neither tight nor baggy.
And they look great for a long time after many, many washes.