The answer is yes, most water based personal lubricants have a negative effect on sperm. This doesn't mean that personal lubricants can be used as a form of contraception. Personal lubricants do not provide contraceptive protection.
But they do seem to have a negative impact on sperm, and if you're trying to get pregnant it is best to avoid most commercial lubricants. There are sperm friendly lubricants available and while they are more expensive, if you can afford it, it's worth it.
If you're interested in the why of sperm-killing-lube, there are two issues to consider, the motility of the sperm (their ability to swim) and the longevity or viability of the sperm (basically how long the sperm is good for).
A 1996 study that was published in the International Journal of Fertility and Menopausal Studies examined the impact on sperm motility and viability from four commercially available personal lubricants (K-Y Jelly, Astroglide, Replens, and Touch) and two vegetable oil products (including Canola oil). They took samples of sperm and mixed them with the lubricants and then measured the effects at 1,15,30, and 60 minutes.
They found that all four of the commercial lubricants inhibited sperm motility by 60-100% after 60 minutes. This effect was similar to the use of nonoxynol-9, a common spermicide found in contraceptive foam and jelly.
The found that the Canola oil had no negative effects on sperm.
These results have been replicated in a non-clinical setting as well. I spoke with a chemist at Davryan Labs (the makers of Probe) who carried out their own lab tests and found that all sperm were dead within 24 hours, and most within the first couple of hours. The chemist at Probe suggested that the PH variance, salinity, and preservative in lubricant were likely the cause of damaging sperm.
If you're trying to get pregnant and you either want to or need to use a lubricant, you have a few choices. Some people say that you can use pure glycerin as a lubricant (but if you are prone to yeast infections this may not be a good option). I have also read about people using egg whites, but I haven't been able to find any research related to the safety of this.
Kutteh, W., Chao, C., Ritter, J., Byrd, W. Vaginal lubricants for the infertile couple: effect on sperm activity. International journal of fertility and menopausal studies 41(4), 1996.