Vaccines - Used to be think people would only harm themselves by not getting vaccinated, but now I know that's not the case, and am in favor of requiring children to be vaccinated. (More liberal)
I've always been against using conservative and liberal to describe specific positions but
come on. It should be quite obvious that extremist nutjobs on both sides are anti-vaccine, but it is far more prominent on the liberal end of the spectrum. The right wing is just crazy libertarian purists who are insignificant and a few nutty religious folk though less than you might expect as most are actually rational. Aren't like 60% or 80% of anti-vaxxers liberals? And the general population only has 20 or 30% describe themselves that way.
It's not an actual stance of any sane ideology, but the ones who hold that stance tend to be liberals.