Conflicting evidence about the extent to which men's semen quality declines with age -- likely lowering their fertility -- is being cleared up by new University of Otago research that has collated and reviewed data from 90 previous studies from around the world. After conducting a systematic review and meta-analysis of the studies' data, researchers from the University's Departments of Zoology and Anatomy found consistent age-related declines in semen volume and sperm performance and increases in malformed and DNA-damaged sperm. Semen quality is regarded as a proxy for how fertile a male is. Study lead author Dr Sheri Johnson says that understanding how age affects fertility is becoming increasingly important as couples delay childbearing toward later stages of their lives. It is well recognised that reduced sperm performance can affect pregnancy success, but it is less well known that the quality of the sperm, particularly DNA quality, could affect the development and health of the offspring," Dr Johnson says. Their Marsden-funded study appears in the international journal, Ageing Research Reviews.
Researchers say it becomes more difficult for men to father children as they age, especially if their female partner is older, too. Men, on the other hand, constantly produce new sperm and some men past the age of 80 occasionally father children. That fuels the myth that men remain fertile all of their lives and can parent children as long as they can perform sexually. Researchers led by Dr. Guy Morris from the Centre for Reproductive and Genetic Health in London have concluded that IVF success rates decline significantly among men over age 51 — coincidentally, the same average age that women enter menopause.
Why age matters for men and women who want to have a family. We all know someone who had a healthy baby in their late 30s or early 40s. But of all people who try for a baby at a later age, many will not have the baby they hoped to have.
Women face the brunt of societal pressure to have children before a certain age, but a new study concludes that the so-called biological clock is a concern for men, too. The authors suggest that more men may want to consider banking their sperm if they intend to wait until later in life to start a family. The paper, published in the journal Maturitas, is a review of the medical literature on older fathers, defined as starting between the ages 35 and 45, depending on which researchers you ask. It highlights studies showing a variety of increased health risks incurred by the partners and children of these older dads. In expectant mothers, conceiving a child with an older father was associated with a higher risk of gestational diabetes and preeclampsia a complication marked by high blood pressure and swollen feet and legs.