(Alfred Kinsey Male Sexuality) For the US population, the sources of first ejaculation are, in order…

For the US population, the sources of first ejaculation are, in order of frequency, masturbation (in about two-thirds of the males – 68%), nocturnal emissions (in an eighth of the cases – 13%), heterosexual coitus (in one boy out of eight – 12.5%), and homosexual contacts (in one boy out of twenty – 4%) …