Advanced paternal age and time to pregnancy/male fecundity
Fecundity is defined as the likelihood of achieving a pregnancy in a defined period of time. Using time to conception as an index to measure male fecundity, there is a significant decline in male fecundity with advanced paternal age after adjusting maternal age and other confounding factors.
For men older than 40 years, the odds ratios for conception in <12 months are 0.62 for 30–34 years old, 0.50 for 35–39 years old and 0.51 compared to the reference age group (<25 y). Association of paternal age with fertility is contradictory. This may be attributed to the decline in male sexual activity as frequency of intercourse decreases with age. The general consensus is that paternal age is associated with reduced fertility especially in couples where men are older than 40 years and age of the women is at least 35 years.