The Juice: Launder First
Do you really have to wash new clothes before you wear them for the first time? The answer is YES, but maybe not for the reason you're thinking . . . Some people do it because they're worried they might catch some sort of nasty rash someone else had when they tried it on. But apparently that almost never happens.
Viruses, bacteria, and funguses don't really transfer to fabric very well. So even if someone DID have a crazy rash, your chances of getting it are almost zero. The REAL reason you should wash new clothes before you wear them is because of CHEMICALS they might be coated with. Sometimes companies spray them with preservatives like formaldehyde to prevent mildew while they're being shipped. And THAT can cause a rash, especially if you have sensitive skin. The one time you should definitely wash something before you wear it is if it's something intimate, like a bathing suit or lingerie.
Your chances of catching something are slightly higher if your GROINAL region comes into play. So wash stuff like that before you wear it, and always try it on over your underwear.