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Sex and Gender

What Do We Mean by Sex and Gender?

At Women’s Health Research at Yale, we are committed to advancing the health of a diverse society. We do this in large measure by studying the health of women and the similarities and differences in health outcomes between and among women and men. As we pursue our work, it is particularly important to use language that captures the different concepts of sex and gender so that our science and our findings can be more precise, respectful, and better serve everyone.

For example, while most people are born biologically female or male, rare biological syndromes can result in genital ambiguity. Or a resistance to a sex hormone can result in traits typical of the opposite biological sex.

Moreover, while an individual’s internal sense of gender can be female or male, some people identify as nonbinary — neither female nor male. Other individuals can identify as a gender that is the same as (cisgender) or different from (transgender) the one assigned at birth. These terms are separate from an individual’s sexual orientation. Sexual orientation describes a person’s emotional, romantic and/or physical attachments (such as straight, lesbian, gay, asexual, bisexual, and more).

In science, as our understanding grows, so must the precision of our language in communicating what we know. Here are some current terms defined in Yale’s “Guide to Gender Identity and Affirmation in the Workplace.” Understanding these definitions can help us all be more precise and respectful of everyone.


Cisgender: A term used to describe an individual whose gender identity aligns with the one typically associated with the sex assigned to them at birth. This is a term that is preferable to “non-trans,” “biological,” or “natal” man or woman.

Gender: A set of social, psychological, or emotional traits, often influenced by societal expectations that classify an individual as either feminine or masculine.

Gender nonconforming: A person who views their gender identity as one of many possible genders beyond strictly female or male.

Intersex: Describing a person whose biological sex is ambiguous. There are genetic, hormonal or anatomical variations that can make a person’s sex ambiguous (e.g., Klinefelter Syndrome, Adrenal Hyperplasia).

Sex: Refers to biological, genetic, or physical characteristics that define males and females. These can include genitalia, hormone levels, genes, or secondary sex characteristics. Sex is often compared or interchanged with gender, which is thought of as more social and less biological, though there is some considerable overlap.

Transgender: A term that may be used to describe people whose gender expression does not conform to the cultural norms and/or whose gender identity is different from their sex assigned at birth. Transgender is also considered by some to be an “umbrella term” that encompasses a number of identities that transcend the conventional expectations of gender identity and expression, including transgender man, transgender woman, genderqueer, and gender expansive. People who identify as transgender may or may not decide to alter their bodies hormonally and/or surgically to match their gender identity. Sometimes shortened to the term “trans.”