Why is Elena the only female werewolf?

Excuse me, but I'm intrigued by the mention of Elena being the only female werewolf. Could you elaborate on the reasons behind this uniqueness? Is it due to a rare genetic mutation, or perhaps a cultural or societal norm that restricts the transformation to females? Are there any other female werewolves in the story that simply haven't been revealed yet, or is Elena's case truly an exception? Understanding the context and motivations behind this detail would greatly enrich my comprehension of the narrative.