legal vs legitimate

LEGAL (法律的,合法的): complying with law;connected with law.                         e.g. legal aid, legal advice, legal action
LEGITIMATE (認為正當): fair, morally or ethically acceptable or reasonable-        allowed and acceptable by law.e.g. legitimate child, legitimate excuse, legitimate question
It may be legal to infect a computer with a virus, if there is still no law against it. But it isn't legitimate.
Gay marriage is not legal in some places, but some people think that they have a legitimate claim for it to become legal.