Men who are struggling to make their partner pregnant could boost their chances by taking antioxidants, new research suggests.
Vitamins and minerals such as vitamin E, L-carnitine, zinc and magnesium may boost the quality of sperm, according to a review of 34 trials.
Experts from the Cochrane Library analysed trials which dealt with male subfertility in more than 2,800 couples.
All were receiving help with reproduction, such as having IVF or sperm injected directly into the women's egg.
The experts noted that chemicals called reactive oxygen species (ROS) are thought to cause damage to cells, in particular sperm cells, which may result in lower sperm counts and interfere with the ability to fertilise eggs.
The damage caused by ROS could be cut by taking antioxidants, the review suggested.
A couple is more likely to go on to have a pregnancy or live birth if the man is taking antioxidants, but which type of antioxidants and in what doses needs further research.