When women started going to work, it was assumed that men would start to pick up the slack in the domestic duties where she would fall short. This is unfortunately not the case in many homes. The reason for this is partially biological, and partially because although women have come a long way, there is still a long way to go before they are on completely equal footing with their male counterparts. After all, it is difficult for people to let go of the gender stereotypes that have been held onto for generations.
Although there are some households where the men do share equally in the household chores, there are many more where this is not the case. There are some domestic duties that have to be performed by women, because they are a matter of biology. Of course, these are pretty much limited to pregnancy, childbirth, and breastfeeding. No matter how far women may come in their quest for equality, men will never be able to do these things without unnatural medical intervention. Because of these biological functions, however, women tend to create more of a bond early on with their children, and this sets a precedent for women to take on the lion's share of the childcare from an early age, whether they are working or not.
When it comes to household chores, such as cooking and cleaning, women are historically considered "better" at these things. This long-held belief, although it is often untrue, leads many men to depend upon their wives for these things. Many of the men who hold these beliefs have grown up in homes with more traditional gender roles. As a result, they do not understand the necessary work it takes to keep up a home.
However, men are not completely to blame for this inequality. Many women have grown up in very traditional homes as well, and tend to take over many of the household duties believing that it is their job, even when they are working. This often includes duties such as cooking, cleaning, and childcare. Their husbands may be more than willing to help them, but many women have been fed an image from an early age of "Supermom," who goes to work every day, keeps an immaculate home, cooks healthy gourmet meals every night, is a perfect mother and role model for her children, and still manages to keep a positive attitude at all times.
True equality may be possible at some point in the future, but society has a long way to go before this happens. Men will need to offer to help more, and women will need to accept more help before true equality is possible. Domestic duties are one of the areas where traditional roles are still accepted, whether both parents are working or not. This is evolving as more and more men and women take on the roles that have been traditionally held by the opposite sex, but it will take some time.