Women’s mountain bikes are made in different frame sizes from men’s bikes. That’s really the biggest difference between them. A six foot tall man needs a different frame than a five foot six inch tall woman; and bike manufacturers understand this. The models may also be different, but not substantially so. Color scheme would be the most obvious example.
A man probably wouldn’t be interested in riding a pink bike. Women’s mountain bikes, however, have no real compulsion not to be a color such as pink. But a pink frame that’s a few inches smaller in most dimensions is not an inferior product, just one marketed to a different consumer.
Thankfully Women’s mountain bikes are one of those products that are marketed to women without resorting to blatant sexism. You won’t find a woman in stilettos and a mini skirt selling you a mountain bike, because that’s not what mountain bikers are not about that. Oh sure, they may get dolled up and go out on the town, but they won’t be doing that with their bike in tow.