A 2019 study of buttock tissue from 10 male and 10 female body donors found that men had more, smaller fat pockets (about 10 versus 7.5), which means more connections between the skin and the layer below it. It also took significantly more force to break those connections in men. In other words, women's tissue holds fat back less firmly.
An MRI study found that women with cellulite had deeper indentations of fat into the skin and a higher share of bands running perpendicular to the surface. Men's bands tend to run in a criss-cross pattern that keeps the surface flatter.
Men's skin is also thicker on average, which hides more of what's going on underneath.