Men can produce sperm throughout their lives, so there is no “male menopause” when men can’t have children any longer. But that said, studies have shown that male fertility does decline with age.
If a man is over age 45, it can take five times longer for him and his partner to conceive than if he was aged 25 or under. When the man is over 40, he and his partner are 30% less likely to conceive during a 12-month period than if the man is under 30.
Male age affects IVF success rates too. One study found that when both the man and the woman are aged 35-39, they have a conception rate of 29%, but that drops to 18% if the woman is aged 35-39 but her partner is five or more years older.
Male fertility happens gradually.
Women tend to see their fertility drop off steeply in their late 30s and 40s, but for men, fertility lessens much more gradually, and from a later age. Male fertility generally starts to fall in their 40s and through their 50s.
A French study found that women’s reproductive capability drops from age 35, but for men it’s only from about age 40. Other research concluded that before age 34, there was no noticeable change in sperm concentration, sperm motility, sperm morphology, or sperm volume, but that after 40, sperm concentration and sperm morphology had both declined.