A study made in Uppsala university, Sweden. Have found that drinking tea changes the genes in women.
It's not in the way of mutation but it changes what genes are "on" and what genes are "off". This have been known to be able to change depending on for example your diet and now we know that tea is one part of your diet that can change that.
Mens genes are not changed by tea and coffe does not have the same effect
The genes that are changed is cancer and estrogene genes and it's not known if the changes are good or bad (but if you consider other studies I can bet it's for the better)