No. Infertile means infertile. One sperm can not fertilize an egg. It takes thousands of sperm because they produce a chemical that weakens the walls of the egg. Without the weakened walls, One single lone sperm has no chance at all.
If you think you may have gotten a woman pregnant, go to the doctor and have your sperm count or infertility double checked.
Yes, I agree! Is there some kind of miracle that you are diagnosed already to be infertile and then be able to make a girl pregnant? Probably, your doctor is making a wrong diagnoses about your sperm. Got it double check to find out. Or are you sure,you are really the father of the child? Double check everything and try to find out the truth.