Sterility as defined by Meaker "is the inability to initiate the reproductive process." Infertility he defined as "an all inclusive term embracing any degree of conceptive capacity below the level of physiological perfection." We prefer the use of the term "lowered fertility."
The exact incidence of barren marriage is difficult to determine. Most authorities believe that between 10 and 15 per cent of adult marriages are barren. In these the male is either a contributory or sole cause in 30 to 50 per cent of the cases.
Clinically it is easy to label a marriage "barren" if defects are found which would obviously prevent conception. However, in those couples in which only a reduced fertility, and not an absolute sterility, is found, it is difficult to establish exact criteria for barrenness. In this there has been considerable disagreement, and consequently we have had to be more or less arbitrary in
MICHELSON L, MICHELSON R. FERTILITY STUDIES OF THE MALE IN BARREN MARRIAGES. JAMA. 1947;134(11):941-944. doi:10.1001/jama.1947.02880280017004