A recent study has shown that deficiency of vitamin D may be a factor among men who are unable to impregnate their partners. The discovery surprised the researchers, who were investigating the incidence of DNA fragmentation of sperm.

Fertility specialist Dr. Anne Clark screened the blood of almost 800 men with fertility problems, and found that almost a third had lower than normal levels of vitamin D.

Sunlight is a major source of vitamin D and levels can also be boosted by supplementation