Male for the same reason as OP. I mainly listen to Rock, and that mostly has guys singing.

Personally, I greatly prefer male vocals, but it is because heavy metal is by far my favorite type of music for nearly 20 years.

I mostly listen to metal with female vocalist such as Nightwish, Epica and Arch Enemy.

Male, just because most of the bands I like have male signers. But there is a lot of great female signers in metal bands ,Alissa White-Gluz for example is better than most male signers.

I mostly listen to post-hardcore/metal/Alternative/Rock which typically have a male vocalist, so I guess male. I do like female vocalists though, been listening to CHVRCHES and Sia a lot for an example.

Both. I like them deep and powerful, I hate whining voices and whining singing style (like Mariah Carey's). For males I generally don't like tenors very much, but I can like some screeching voices, like AC/DC's Brian Johnson.

Amongst my favourite voices there are:

Males:
David Bowie
Freddie Mercury
Elvis Presley
Fabrizio De André
Jim Morrison
Eric Burdon
Joey Ramone
Mick Jagger
Dave Gahan

Females:
Linda Ronstadt
Grace Slick
Cecilia Bartoli (mezzo-soprano opera singer)
Dionne Warwick
Françoise Hardy
Nina Persson
Paola Turci

...and many others.

I usually prefer women vocals. The ones I like to listen to sound just to great to the ears, though a lot of the songs I like are Japanese or Korean, and the not so known ones. I`m either or really. If the singer is good along with the song, I`ll like them.

It's a big surprise given your  age!:P

Female, easier to listen too.

Both.