STD rates are very low for lesbians. God must love lesbian behavior.
Yes, I too have seen evidence that the STD rate is much lower for lesbians than for gay men. Disease rates are much more closely linked to number of partners, not to orientation, and lesbians are less likely than gay men to be stupidly promiscuous.
Lesbian rates of mental/emotional illness and domestic violence, however, are way up there. The dynamics in these relationships are somewhat unbalanced.