Obesity can have a negative effect on sperm quality

"There are indications that fatty acids may be part of the explanation for the link between obesity and poor sperm quality," says Andersen.

'The beneficial fatty acids are basically not able to enter the sperm cells and this can contribute to poor sperm quality, particularly in relation to the sperm’s shape and motility. It may be both diet and the circumstances surrounding the obesity that lead to lower levels of DHA fatty acids in sperm.'

'Overweight is unfavourable both for sperm quality in itself and for the fatty acid composition in sperm cells, which is an important factor in sperm quality,' says Andersen."