The biological explanation

Whenever journalistic articles on current issues quote some scientist explaining away our social or sexual behavior on the basis of what primitive man once did, they always revert to the biological imperative (women choose men based on which one will give her the healthiest children, thus insuring the survival of the species, etc. etc.) I don't find such ethnobiological explanations persuasive or illuminating. They give an illusion of explaining something essentially mysterious. They replace instinct with rational motives, if not man's, then nature's, but nature may have reasons our minds know nothing of. The biological explanation reduces emotions such as love to chemistry. It seeks a lowest common denominator explanation for age-old questions, but it is no more than a spasm of the mind.