I'm not a vegetarian, by choice. But protein is protein: it's a myth that animal protein is "necessary" or superior in some way.
The only danger I know about that strict vegetarians confront in their diet (I mean vegans, not ovo- or ovo-lacto-vegetarians) is a lack of vitamin B12. Supposedly this lack can be overcome by supplements.
Lots of tough vegetarians of various descriptions out there--as previous posters have testified!