Animal Sperm Quality Unaffected by Age

Human-like decline in male fertility with age is not consistent across various animal species.

University of Oxford-led study examines 379 studies covering mammals, insects, birds, and fish.

Age does not impact ejaculate size, sperm quantity, motility, or viability in most animals.

Surprising positive effects of age on reproductive traits observed in many insect species.

Lab rodents show age-related deterioration in most measured ejaculate traits.

Lack of consistency suggests uncertainty about universal age-related deterioration in ejaculates.

Contrast in aging patterns between animals and humans linked to increased human lifespan.

Men living beyond evolutionary age may contribute to age-related sperm function decline in humans.

Stronger selection pressures in animals may drive the maintenance of sperm function across all ages.

Reproductive outcomes, including fertilization success, show no consistent trend with advancing age in animals, contrary to humans.