Singular.
The Webster definition is conventional. First it says a woman is a female. Then it explains how ‘woman’ is combined with other words such as ‘councilwoman’.
Its #1 definition of ‘female’ is “of, relating to, or being the sex that typically has the capacity to bear young or produce eggs”
They wander into the meaning of ‘gender identity’. That definition is
“a person’s internal sense of being male, female, some combination of male and female, or neither male nor female”