Does water based lubricants affect sperm?
Sure, anything they come into contact with affects them. Increased lubricant means increased fluid for them to swim in. If the lubricant is slightly basic pH then it can counteract the natural acidity of the vagina increasing the likelihood that the sperm survive and reach the egg for fertilization. However if the lubricant is spermicidal, then it destroys the sperm cells immediately upon exposure. Also if the lubricant is either hyper or hypo osmolar this too can damage the sperm.