coke, pepsi

Drinking lots of cola may reduce fertility rate, according to researchers: http://www.foodconsumer.org/newsite/Nutrition/Food/cola_may_lower_sperm_counts_3103100905.html

According to the Danish study, men who drank a quart or more of cola had 30% less sperm count than men who did not drink cola.

The men who drank more than one liter per day of cola had only 35 million sperm per mL compared to 50 million sperm per mL for those who did not drink cola.

Caution needs to be exercised when the study results are interpreted as the study is not a trial and it did not reveal any causal relationship between drinking cola and reduced sperm counts.

Many things can be involved in the association, but the researchers told Reuters that caffeine may not be one of them.  Lifestyle may be a determinant as  those who did not drink cola tended to follow a healthier lifestyle.

This may explain why polars bears are nearly extinct.