The dissimilitude between the terms 'civil marriage' and 'civil union' is not innocuous. It is a considered choice of language that reflects a demonstrable assigning of same-sex, largely homosexual, couples to second-class status. For no rational reason the marriage laws of the Commonwealth discriminate against a defined class; no amount of tinkering with language will eradicate that stain. Barred access to the protections, benefits and obligations of civil marriage, a person who enters into an intimate, exclusive union with another of the same sex is arbitrarily deprived of membership in one of our community's most rewarding and cherished institutions. That there may remain personal residual prejudice against same-sex couples is a proposition all too familiar to other disadvantaged groups. That such prejudice exists in not a reason to insist on less than the constitution requires.
   —The Massachusetts Supreme Court

From: "Top Ten Reasons for Conservatives to Oppose the Federal Marriage Amendment":

And lastly, whats the real danger here? I mean, if gay "marriages" are recognized, does that somehow diminish my own marriage...or yours? No. Does that mean heterosexuals will suddenly stop pining for the opposite sex and "turn gay"? No. Will gay marriage mean men and women will stop having children and doom mankind to eventual extinction? Come on.