Nah, those studies have been bunk for a while and they rely on the comparison of first, second and third world nations as if they're all the same when they're not alike nations. The perpetuation of this myth has actually created serious harm in third world countries where they perform incredibly nasty "circumcision" in unclean environments with rusty utensils on adults and proceed to have unprotected sex thinking that they're now safe.

What's more is that STI's have virtually nothing to do with hygiene. You can't wash away chlamydia. Herpes isn't solved with a bit of soap. That involves actual medicine and/or protective prevention, which means the idea that circumcision helps prevent STIs completely bunk. The ONLY argument is hygiene, at which point you might as well advocate that we lop off the ears of every newborn because some people don't clean them well enough.