It's just another responsibility, however it supersedes all other responsibilities. It's no doubt that taking care of a child takes a lot of effort, and historically, women have been expected to be the primary caretaker of a young child. Even though society's progressing, that still ends up being the case most of the time.
Women's lives and careers are more effected by children since they undergo physical, emotional, and anatomical changes before, during, and after pregnancies. In fact, women are more likely to take off from work to care for children more than men. Specifically, women are more involved in domestic roles, economic roles, and mental health and well being roles regarding the child.
I use the same time . I think ur really cool . I take it to the movies . I am an actor / model I have played a role in the world . However did we forget that a president was assassinated while being driven in a vehicle ?
Although having children won't necessarily affect a woman's career negatively, it generally does. Some people are better at juggling their time and responsibilities than others, but having a child takes a whole lot of time and effort which might conflict with a career (which also takes a whole lot of time and effort). Pregnancy takes a physical and emotional toll on a woman, and it most likely also take a toll on her career.
Society needs children. Women too.
Women and men need something to work (or live) for.
This "something" is usually called family.
At the end of their lifes, all the "career" concept remains an empty bag.
Moreover, having somebody to fight for (more than the egocentric oneself) can be a great career stimulus.