Although men maintain their fertility much longer than women do, increasing evi­dence is showing that later-in-life fatherhood may carry some increased risk of birth defects for their children. Scientists have found changes in the DNA of older men’s sperm. Some studies suggest that single-gene mutations may be four to five times higher in men age 45 and older compared to men in their 20s. Increases in rare birth defects, autism disorders, and schizophrenia have been associated with higher paternal age (Rabin, 2007b).


The full term of pregnancy usually lasts about 40 weeks from the last menstrual period, although there is some variation in length. Some women have longer pregnancies; oth­ers give birth to fully developed infants up to a few weeks before the 9-month term is over. The experience of childbirth also varies a good deal, depending on many factors: the woman’s physiology, her emotional state, the baby’s size and position, the kind of childbirth practices used, and the kind of support she receives.