Is it true that stds are more common if a guy is uncircumcised?

Yes, for some STDs: Recent evidence has supported the facts that uncircumcised makes have be more prone to hpv rates as well as, in developing countries with high HIV rates, HIV as well. It is not really associated with other STDs (chlamydia/gonorrhea). Also, though not an std, partners of uncirc males may be more prone to a vaginal condition called bv. It's important for the make to have good foreskin hygiene.