Sen. Lindsey O. Graham. (The Washington Post)

So Lindsey Graham is a single, never-married man who is running for president. This week, he offered up the PG idea of a "rotating" cast of first ladies, including his sister.

And, naturally, people have made all sorts of jokes about all of that.

But the truth is, the single, never-married population in the United States isn't small. Neither is the single, never-married and childless contingent. Or the married without child. In fact, they are fast-growing groups, representing substantial and increasing portions of the American electorate.

But despite the fact that more than 100 million American adults are single and never married, there’s still a fair amount of single-person suspicion baked into the culture.

There are the often homophobic inferences about sexual orientation. Then there is the frequency with which mothers and fathers are routinely presumed to be safe, never-threatening human beings. (Never mind that parents are responsible for a substantial portion of child abuse in this country each year, and certainly commit other crimes and cultural misdemeanors.) And, of course, there are all the many, many ways that the tax code piles tax credits and deductions on parents, while social services for healthy, single, childless adults remain limited.

Reasonable questions and solid social science do exist about what role wages, divorce rates and various social attitude changes play in swelling the ranks of America’s single, never-married population. We could debate which of these issues are driving the growth in single, never-married adult status and whether these should be matters of public concern. We could even very seriously question whether the country should spend millions on marriage promotion programs or whether childlessness is bad for the country. There are real reasons that Kate Bolick’s “All The Single Ladies,” published in The Atlantic in 2011, remains widely read.

But none of that seems to be part of the snickering, sneering conversation we keep pretending we are not having about Graham, even though we are. There are also a lot of important questions that Graham could and should be asked that have nothing to do with the naked state of his ring finger.

So, Lindsey Graham is single and never married. Okay. So, too, were 35 percent of the people who voted in the 2010 midterms and 38 percent of those who cast ballots in 2008, according to Census data.

Perhaps having Graham as a candidate can crush some of the remaining stigma.