A lot of studies regarding penis length are self-reported. So basically subtract an inch from the results and you get a more accurate picture.
It's also why countries that censor genitals in porn report smaller penises than countries where the race of the local population is heavily fetishized wrt. supposed "big dicks". When actually measuring, all those differences become smaller than is statistically relevant.
Fuck ads, obviously, but I can understand there's confusion here.
If GPC says "do not sell my data", but the user subsequently opts in via the cookie banner (or vice-versa), you have two conflicting signals. There's no clear case law or anything that says what to do. Or what should happen if the same user sends different GPC signals depending on their device or browser.
Although I guess the easiest solution is just "do not sell data if any signal suggests it's not allowed", but that doesn't line advertisers' pockets I guess.