What is the symbol for same-sex marriage?

Although there is no official symbol for gay marriage, when Miley Cyrus wanted to get a tattoo representing gay marriage, she had a equal sign ("=") tattooed on her ring finger. A similar symbol often seen at gay marriage rallies is the symbol for the Human Rights Campaign (HRC), which is a blue flag with a yellow equal sign which represents equality. Occasionally, you will see symbols composed of wedding rights colored in with the rainbow spectrum, since the gay pride flag is rainbow colored. You will also see permutations involving the scientific symbols for male and male (or female and female) worked into a representation of gold wedding bands. Also, a cake-topper with either two grooms or two brides would be instantly recognized as a symbol for gay marriage. Somewhat less easy to recognize would be the ADA-compliant silhouettes usually used on restroom doors (again male and male or female and female) holding hands.

UPDATE: Proponents of same-sex marriage seem to have settled on the white knot as a symbol of support for marriage equality. This is similar to the red one for HIV/AIDS awareness, the pink one for Breast cancer, etc.