When discussing transgendered individuals, people use the term biological female ,to mean someone was born female, even if they are transgender now and identify as something else.
Yes all females are biological females, but this terminology is normally used only when discussing transgender people.
Too bad. There is knowledge of it now. Wonder if the Freedom of Information Act could be put into play here now.
What they mean is genetic. Even eunuchs posing as women are "biological".
But to keep it concise, here is the correct mapping.
trans woman == eunuch
biological woman == genetic woman == woman