Uh, no, not really. Women are perfectly capable of defending themselves while pregnant, particularly in the early stages where being with child doesn't really impair a woman in the slightest (in fact, in the last few days before giving birth, women often get a rush of energy and activity). In fact, there are many anthropological studies that report different tribes giving men and women different roles (such as one tribe giving basket-weaving to men while another gives it to women, one tribe giving agriculture and housekeeping to men and another giving them to women, and so on).Techno Squidgy said:
If you ask me, the origin of oppression began with segregation. When men and women were segregated to be socialised differently (out of biological reasons, yes, but it was completely unnecessary), and the different socialisation led to both genders being unable to understand each other because each was being taught things that the other had no clue about. And since fear of the unknown is the strongest fear, men felt the need to control women, because they were unknown, and that made them dangerous. This rationale is also observed racially. A lot of races warred with, enslaved and killed other races because they saw them as different and unknown.
A man will trust another man from the same race/tribe because they were both socialised in the same way. They both engage in the same tasks and are often physically placed in the same areas. That man will not trust a woman of his own race or a man of another race (and much less a woman of another race), because he doesn't know them. He doesn't know what they think, what they value, what they do, what they've been taught, and so on.
This is why gender roles are oppressive, because they are used as tools to segregate and indoctrinate. A woman who is socialised differently (and even today women are socialised differently than men) is always going to be an unknown to a man, because society has given a discourse that isn't the same as the one it's given women. This is the root of all those "I can't understand women!" and "Men are from Mars, women are from Venus!" things you hear so often. The idea that both genders are irreparably different and must always be apart is the main reason there is still oppression to this day.
That's also why trans and genderqueer people get a lot of flak from pretty much all aspects of society, because refusing to conform to the gender role society assigns to you at birth undermines the necessity of those gender roles. And if those gender roles aren't necessary, then the entire system of oppression built upon them crumbles down.
