I have to agree with Abraham, Leto, the "Determine Gender" ability is available for doctors before career level 10.
In Sunset Valley, Geoffrey Landgraab starts at level 7 in the Medical Career and he is able to "Determine Gender" when asked. I now forget which doctor in RV has this ability but Jebidiah Wilson starts at level 5, as does Shirley Lin, and Marisol Lobos starts at level 4. In TB, I believe Nick Knack can "Determine Gender" and he starts at level 6, Shamus Drudge is level 5, and Molly Coddle starts at level 1. I don't know what level the AP doctors are at the start of a new game but it's worth checking in to.