Biological clock may refer to:
- Circadian rhythm, living organisms' adaptations to solar related rhythms
- Age and female fertility
Famous quotes containing the words biological and/or clock:
“Biological possibility and desire are not the same as biological need. Women have childbearing equipment. For them to choose not to use the equipment is no more blocking what is instinctive than it is for a man who, muscles or no, chooses not to be a weightlifter.”
—Betty Rollin (b. 1936)
“Stands the Church clock at ten to three?
And is there honey still for tea?”
—Rupert Brooke (1887–1915)