Infertility and Sex
Couples trying to conceive who want lubrication during intercourse are best advised to go to their refrigerator rather than their medicine cabinet. Vegetable oil and olive oil don't have too much of an impact on sperm survival and petroleum jelly is also a relatively safe alternative. However, lubricants such as K-Y Jelly, Sugilube, Alpha Keri & Keri Lotion contain bacteriostatic agents, which can significantly decrease sperm motility. Saliva, contrary to popular belief, is also toxic to sperm. The best option is to use nothing.
Timing is very important. Having intercourse too often may result in fewer sperm and impaired motility, or movement. Infrequent intercourse can also cause sperm counts to drop, or can cause a couple to miss an opportunity to conceive