could be both, but girls since i`m a girl and i get jealous even without a reason

It doesn't matter about gender but it's a natural emotion that appears. Anyone can get jealous and over anything.
Guys tend to get physically agressive (not always) but can do something else
Girls tend to get socially agressive (also not always, sometimes emotionally too)

both

I think that it's both. I've read stories about guys who dodn't let their girls go anywhere without their permission (possessive, maybe) for fear that their girls are going to fall for other guys.
There're also girls (and guys) who kill their lover because of they are jealous, too. Love really does make people blind.

guys, because the world is filled with c**k teasers

i would say both^^ even if i am a girl so do i gues boy can too bet jelous^^

well every person is different but if it is coming straight from me i will say........both....... .

it depends on the person really, since i'm a girl, from my experience... the guy gets more jealous.
But, based on looking at other people's relationships, girls can get pretty petty..
so i'd say BOTH :P

i think girls are more jealous. like sometimes i get jealous of other girls with my bf...but my bf doesn't see it at that way yea i think it depends, i asked him one day and i think i get more jealous then he does XP

both can be jealous, depends on person though and experiences...