One of the students in my online copy editing course was taught -- straight out -- that it's wrong to start a sentence with "and." Whenever she did, a high-school teacher would say, "That's not right, dear." Several other students were under the same impression.
Who ARE these teachers who spread this stuff and why don't/didn't they ever check their own facts?
The Chicago Manual of Style, Garner's Modern American Usage, Fowler's New English Usage, the American Heritage Dictionary, and the simple logic of grammar and idiom all say it's fine to start a sentence with "and" (or "but" or "so"). I don't know of any real authority that disagrees.
It's a shame how powerful misinformation can be.