Well until today they couldn't legally consent to committing sodomy either could they?
I don't think the Texas homosexual sodomy issue was a matter of legal consent, but instead a matter of an overall illegal act. That to me is different from sex with a minor -- because a minor can't enter into contracts or legally consent to anything (nore can an animal, by the way). In the first case, it was consensual, but not legal. In the latter, it is illegal and also by definition non-consensual.