What gender is Horntail?

I tend to agree with some others on reasoning that it's a female. I think it's female because female dragons are the more aggressive as with many other animals. Not really going to go into the seduce thing. Gay people seduce each other so therefore guys seduce too. Also, seeing as there aren't really any other dragons around that Horntail can mate with, I guess it can be gay with itself. Another theory I thought of is if Horntail is both male and female. Left and Right heads are male and Middle head is female.