I found this online:
Zinc is the most widely studied nutrient in terms of fertility for both men and women. It is an essential component of genetic material and a zinc deficiency can cause chromosome changes in either you or our partner, leading to reduced fertility and an increased risk of miscarriage. Zinc is necessary for your body to 'attract and hold' (utilise efficiently) the reproductive hormones, oestrogen and progesterone.
And it's equally important for your partner: zinc is found in high concentrations in the sperm. Zinc is needed to make the outer layer and tail of the sperm and is, therefore, essential for the health of your partner's sperm and, subsequently, your baby. Interestingly, several studies have also shown that reducing zinc in a man's diet will also reduce his sperm count.
Vitamin C is also an antioxidant, and studies show that vitamin C enhances sperm quality, protecting sperm and the DNA within it from damage. Some research has indicated that certain types of DNA damage in the sperm can make it difficult to conceive in the first place, or it can cause an increased risk of miscarriage if conception does take place. If DNA is damaged, there may be a chromosomal problem in the baby, should the pregnancy proceed. Whether or not DNA damage does have these effects has not been conclusively proven, but it's worth taking vitamin C and the other antioxidants as a precautionary measure.
Vitamin C also appears to keep the sperm from clumping together, making them more motile.
One study has shown that women taking the drug clomiphene to stimulate ovulation will have a better chance of ovulating if vitamin C is taken alongside the drug. Clomiphene does not always work in every woman, but the chances are often increased when vitamin C is supplemented.