In a list of amendments dealing with quite serious issues, this one would stand out as being the one without any gravity. Just a horrible idea.
If you think that the integrity of the fundamental societal unit is not a matter of some gravity, then I'm not going to be able to explain it to you. I don't mean to be condescending, I once held much the same opinion. Observation and experience has led me to a different conclusion.
Lawrence has put the SCOTUS on a collision course with the institution of marriage. The homosexual lobby can taste it. To prevent that, an Amendment like this is going to be ratified, so your best bet is to try and make sure we get the best one.