Do women get fat easily because they have little muscle mass?

Answer 1

That's a simplified look at it, but yes. A woman needs more calories to produce healthy offspring.

Answer 2

No, weight gain means you are on a calorie surplus. Sure muscle mass burns more calories, but it only matters in context to what you're consuming. 

And even if men are built with a little more muscle, that doesn't mean that women doesn't have that much of a muscle mass. Have a look at the gym and you'll see lots of women with muscles.

Answer 3

No it’s because women need more fat to sustain their bodies. For example protect our uterus, etc. Also women have boobs (balls of fat). This helps so that they can have babies. When they are pregnant that extra fat is essential in order to help sustain both the baby and its mom. It also helps stretch out the stomach. And also so that they can feed their kids. It’s important for them to have more fat to protect their organs.