Coffee and tea both contain certain amounts of caffeine in them. although there is a lot of information on the possible affects of caffeine (harmful or beneficial), the official word is that caffeine does not reduce the chance of fertility.
There is no solid medical evidence that caffeine consumption affects your chances of getting pregnant.
Similarly, there is no evidence that caffeine reduces sperm production or quality.
Once you are pregnant though, it is advisable for women to consume no more than 2 cups of coffee or tea per day as caffeine has been shown to reduce placental blood flow and therefore may lead to low birth weight babies.