There is a growing amount of research diving into sex (biological anatomy) and gender (social construction). If you dig into it and remove emotional and personal motivations, you'll find that the vehement declarations about what is or is not "natural" for humans aren't supported.

1. Effects of gendered behavior on testosterone

Findings indicate that social conditioning and the opportunity to wield power influence testosterone. This is opposed to traditional beliefs that testosterone is primarily tied to biological sex. This means it's unlikely that "men are biologically wired to be dominant" but rather that "men are permitted to wield more power and thus accumulate more testosterone."

Our findings show that discrete events of gender-related socialization may account for some portion of the observed "sex" difference in adult testosterone levels. This adds to growing evidence that gender and sex are more permeable categories than is typically accounted for in bioscientific research.

2. Bitch — on the female of the species

Written by a Zoologist, this book digs into the heavily biased foundation of sex-based animal research. For decades Victorian-influenced scientists threw out any research contradictory to the story that "the female is a passive participant, with its purpose only being to incubate offspring."

In actuality, in significantly large quantities, the female of various species are the drivers of evolution. In many species (hyenas, killer whales, lions, bonobos, lemurs, elephants) the female is the key pack leader. Several animals change their sex from puberty to adulthood; some can even switch sexes as full grown adults.

TLDR: There is nothing inherent to "male-ness" to make them active and nothing inherent to "female-ness" to make them passive. Any binary understanding of gender and sex simply isn't backed by science.

3. The gender-binary cycle

Research from neuroendocrinology, neuroscience and psychology often reveals group-level differences between women and men, but does not support the biological-essentialist beliefs that these differences are immutable, nor the assumption that human brains, hormones and 'natures' belong to two distinct kinds.

Human brains also cannot be meaningfully sorted into 'female' and 'male'. Although there are group-level gender differences in many brain measures, there is a great deal of overlap between the distributions of women and men for each of these measures.

My favorite place to find aggregated research papers is elicit.org.