#1 The first one is at least partly false. That is based off of poor sociological research that is based on a small sample. Basically millions of kids play violent video games, but only a small (read around 1% if not less) show any increase in violent tendencies. I think most kids understand the difference between fantasy and reality.
#2 HOLY HELL! If one more person misinterprets that report again I'm going to flip out! This is the THIRD bloody forum that study was brought up in, and this is the worst yet! ARG! Your friend is idiot for one (or are idiots if multiple told you this). You can't be turned gay or into a woman by wifi. That is impossible.
The study was about wifi having an effect on sperm, specifically on motility and on the DNA itself (wifi causes DNA fragmentation). They basically said that if you use Wi-fi too much your sperm count will possibly lower. ARG!
(btw, I've actually read the full journal article, you can read the abstract here)
#3... I have not heard... I'll look into it... But I some how doubt it... I don't see the correlation with soft drinks and violent tendencies.