Should it be fair game for me to download a movie from "some site I found it on", because I didn't take it from the studio itself? If copyright works through "

Should it be fair game for me to download a movie from "some site I found it on", because I didn't take it from the studio itself? If copyright works through "authorization", I don't see why we should accept it as natural and normal for authorities to use our fingerprints, hair, or even sperm without our permission. Speaking of the last one, I don't think it's legal for a woman to impregnate herself with a man's sperm by taking it from a used condom and without his knowledge?