Any doctor or member know what is it called when leg is almost bare of any hair?

[PatientlyWaiting]

As far back as hair started growing on my hair, which was around 13-14 years old, it grew very sparse, thin, and only in very small patches. My legs are so hair less and thinned hair, from a certain distance it may seem like I shave. This was never a concern for me, and it still isn't, i'm not a short pants/jeans wearing guy, even in the summer. So this isn't even a problem for me. But I am very curious to know what is it called and why was I born with that? And why it only on my legs? I mean other than alopecia areata that started at 22 years old, I don't have any other patchy hair loss. I've googled my problem but can't really find anything, just people who lost leg hair as an adult for their own fault, not something they born with or started naturally in their early teens.

I've attached pictures.

Any information would be appreciated.

[PatientlyWaiting]

I remember in gym class in high school when I was 14-15 I used to shave, because I got tired of classmates asking me why I have hair in only some places.

[Notcoolanymore]

I bet this is a problem many women wish they would have.