It’s not the use of the word “female” itself, but the use of the word as a noun to describe a woman, because it is taken to imply that the woman is a mere object. As the other person who replied to you said: context matters.

I use the word “female” (and “male”) every single day when documenting on my patients, e.g. my notes commonly begin with “Patient is xx years old, female, […].” This is normal and no one would take issue with it, because it is using “female” as an adjective and in a context where the information is important.