studying two identical twins which raised in different environment, would reveal whether the diseases is caused by environmental factors or by genetic factors.
identical Twins have the same genetic composition. So, when they are separated in different environment and one of them get the disease, the most likely cause of the disease would be the environment.
sexual contact between individuals involving penetration, especially the insertion of a man's erect penis into a woman's vagina, typically culminating in orgasm and the ejaculation of semen.
