WATCH: Sorry Ben Carson, Marriage Equality Won't Lead to Polygamy

Presidential hopeful Ben Carson has lashed out at same-sex couples yet again, having previously suggested that prison sex shows that being gay is a choice.

This weekend, Carson hinted to CNBC that if the country allows same-sex couples to marry, it would have no choice but to allow "other groups," including polygamists, to marry as well.

He was partially echoing a question raised by Supreme Court Justice Samuel Alito, who asked, "a group consisting of two men and two women apply for a marriage license. Would there be any ground for denying them a license?"

Attorney Mary Bonauto had a quick answer to that question: The difference between straight couples and gay couples is not particularly significant, from a legal perspective, but marriage between two people is vastly different from marriages involving more than two adults.

As Bonauto pointed out to the court, issues could arise concerning divorce and child custody, medical decision-making, employer benefits, immigration, or inheritance. With two-person couples, the correct course of action on these matters is relatively settled law. But with multiple spouses, the entire marriage contract would have to be overhauled to protect all of the parties in the relationship.

Marriage equality also doesn't lead to marrying children or animals or inanimate objects, since they can't provide consent. For proof, one needs only to look at other nations that have embraced the freedom to marry but still do not allow citizens to marry their pets, children, or washing machines.

It seems probable that Carson, an accomplished neurosurgeon, is aware of that distinction. And judging by his refusal to verbally identify the "other groups" that might try to seek a right to marry, he's also aware that a presidential candidate directly comparing same-sex marriage to polygamy, bigamy, or bestiality isn't likely to poll well. So instead, he let CNBC's John Harwood make the connection, deftly avoiding a headline-grabbing quote from Carson himself.