Viagra risks

Researchers have found that taking Viagra may damage male fertility, leading to warnings about using the drug.

The team at Queen's University in Belfast found that although Viagra makes sperm more active, it also damages their cap-like outer covering. If this is damaged early on, it makes it hard for the sperm to break into an egg and fertilise it.

Some fertility clinics have prescribed Viagra for both women and men, but this research, published in the journal Fertility and Sterility, does suggest that it may do more harm than good for male fertility.