Very generally, male brains tend to react to visual sex signals more than female ones. Women are far less likely to be aroused by visuals, which is why evolution put no effort into making male genitalia presentable while women have elaborate and overt markers of sexual maturity that are generally also considered pretty. It’s also the reason why the porn industry, as the producers of a visual medium, caters to men a lot more than women. It’s simply easier to make porn for men (have lots of the right visual signals and you’re good) than for women (ugh, idk, plot?).

Note: This is a generalisation.