I think I'm missing something. On the Results in study [b], they say
> Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration.
If tea and coffee don't cause an effect, but cola and soft drinks do, doesn't that imply it's sugar, not caffeine?
> Semen parameters did not seem affected by caffeine intake, at least caffeine from coffee, tea and cocoa drinks, in most studies. Conversely, other contributions suggested a negative effect of cola-containing beverages and caffeine-containing soft drinks on semen volume, count and concentration.
If tea and coffee don't cause an effect, but cola and soft drinks do, doesn't that imply it's sugar, not caffeine?