Her parents believed her to be a masculine girl. I doubt they had even heard of dsd. How exactly is one “raised as a girl” aside from her family and peers believing her to be female?
Hang on, how do you know what her parents believed? There's a reference above to Semenya's father using "he" throughout an interview.
We know Semenya was believed to be female at birth (so in the first few hours!), but they had years to find out Semenya was actually male, and there are a lot of ways that could come about. Including just changes during growth.
The evidence does suggest that Semenya was believed to be male at school at least in the years leading up to grade 11 (age 15), at which point that teacher found out Semenya was "actually a girl". (The scout had just been round?)