"Equal but different" is a kind of essentialism attempted to be glossed over with feminism. It is related to the straw-man argument that "feminists are trying to argue that men and women should be 50:50 in everything and treated exactly the same in all regards".
The argument goes that men and women will typically fall into different interests. This is true to some degree, since gender-specific trends do emerge when the sampling is large enough. The realm of fallacy is reached when typical is taken for right, natural, or good, and when what is typical is enforced as a norm. Personal interests are also such a multi-faceted phenomenon affected by so many different factors, that it's next to impossible to say whether a preference is inherent to a person, or a product of cultural, social, and environmental influences.
This rhetoric is used as an excuse for sexist phenomena in the guise of acknowledging and celebrating the areas that women "naturally" prefer. It is also a common form of (man)splaining.
While it is true that women's work is often undervalued due to androcentrism, this argument has some flaws, first among them that it does nothing to address the fact that women hold less power and influence in society. Cordelia Fine in Delusions of Gender states: "Gender Equality 2.0 justifies a status quo in which politics, wealth, science, technology, and artistic achievement continue to lie primarily in the hands of (white) men." (p91) She also quotes Neil Levy (p91), "It is no accident that there is no Nobel Prize for making people feel included."