It is unfair that women have to solely take responsibility to have babies
I know what you mean, but no. Or rather, yes, I suppose it is unfair, but genetic technology has not yet reached the point where men can "have" babies. Rephrase to say what you mean more precisely.
It will be approved by the following analysis.
Unnecessary even if it were right, which it is not. I think you mean "proved" rather than "approved."
people can not access the real happiness without children
Congratulations -- you have just offended most of your childless readers. Acceptable for an argumentative essay on a different topic, but not here. Also, if having children is pure happiness, why should anyone care if men leave all the joy to women alone?
why men do not take care of children and women have to do that.
An excellent question, but not rhetorical. For instance, the obvious answer is because the role falls more naturally to women. It is the women who carry the child for nine months, giving them an arguably stronger bond to the child than the father has. Also, women are the ones who have the biological equipment to feed the child once it is born. Technology has allowed men to potentially feed child milk from other sources, but it doesn't change the basic biological imperatives or alter gender-based psychology, no matter how much some people wish it otherwise. This is not to say that your argument is wrong, btw. You can in fact make a very strong case for your thesis. But even in a TOFEL essay, you shouldn't ask rhetorical questions that are likely to provoke an answer that works better for the opposite side.