Gentail warts are very contagious, it can spread by direct skin to skin contact example: sex, oral sex, anal sex, vaginal sex, from beeding, clothing and even from mother to baby during childbirth..
The disease has an incubation time of anywhere from 2 to 9 months, so you may not even realize that you've got it, so you could unknowingly spread it or find it by someone that doesn’t realize that they've it.