ABSTRACT
Sex and affection have appeared at different times and have different origins. Affection appeared much later than sexual reproduction and for a long time anonymous sex, without personal bonds and affectionate connotations, was all that existed within the animal species. In human sexual love, however, reciprocal attention favors being in tune and pleasure for both partners, in an intimate relationship attentive to reciprocal preferences and reactions, that can be explored and strengthened over time. The union between sexuality and affection in sexual love profoundly affects the human sexual relationship and distances it in a radical and definitive way from imposition and violence. In humans the kiss has passed from the parental to something shared between adults to indicate positive sentiments, spanning from friendship to sexual love. The more conspicuous physical structure of males and the smaller one of females function to enact a rapid sexual encounter based on a rapport of dominance and submission.
