Christmas drinking sinks sperm
♦ Men produce the strongest sperm in spring and autumn, according to the largest study of its kind.
Experts think that sperm health may be linked to the number of daylight hours and the fact that men do more exercise than during the winter.
Men are also likely to drink less than at Christmas or when they go on a summer holiday.
The study by the Icahn School of Medicine in New York involved samples from 29,000 men over 17 years.