Being that men are visually stimulated and are wired to their carnal appetites, Talmudic teachings are brutally frank and aware of man’s flaws. Various regulations were taught to prevent sexual improprieties from sullying a person’s holiness and closeness to God.
Recognising female attraction, and taking into consideration male hormones, the Talmud is quite forthright and blunt regarding how a woman’s’ innate modesty is to be protected. Leviticus 18:16 teaches,
“None of you shall approach a female to uncover her nakedness: I am the Lord.”
From this, the Talmud derives a prohibition against any intimate contact with a person with whom one is forbidden to have sexual relations. This “intimate contact”, includes even a handshake, as strange as this may seem. (Of course, physical contact is permissible between grandparents, parents and children.)