Marco Rubio should have to choose.

You can pretend that it's quite possible that the planet we live on is about 6,000 years old, and you can have a seat on the U.S. Senate committee that deals with science.

But you shouldn't be able to do both at the same time.

I think it's only fair that when you reach the highest legislative body in the land, you should have to pick between willful ignorance and reality.

And your seat on the science committee should hang in the balance.

While there's no way of preventing U.S. senators from holding the notion that the Earth is only a few thousand years old, common decency should keep them from taking up space on a committee dedicated to science, a discipline that has through empirical evidence put the age of the Earth at about 4.55 billion years old.

Choose, Mr. Rubio. Six thousand years or 4.55 billion years?

It's not like we're splitting hairs here.

In this month's issue of GQ magazine, the junior senator from Florida tries to have it both ways, saying that the age of the Earth "is one of those great mysteries."

What's not a mystery by now is that Rubio is already running for president in 2016, and by claiming the age of the planet is little more than a matter of equally valid opinions, he's going out of his way not to offend any Republican primary voters.

"I am not a scientist ..." Rubio said in the interview. "At the end of the day, I think there are multiple theories out there on how the universe was created and I think this is a country where people should have the opportunity to teach them all.

"I think parents should be able to teach their kids what their faith says, what science says. Whether the Earth was created in seven days, or seven actual eras, I'm not sure we'll ever be able to answer that."

I agree. Parents should be able to teach their kids whatever they want. But grownups shouldn't be allowed to sit on a congressional science committee when they treat Earth science as if it were little more than some boxers-or-briefs debate.

The next thing you know, congressmen sitting on science committees will start imagining that female rape victims can avoid getting pregnant through willpower.

Rubio doesn't have to pretend to be so bamboozled by the Earth question.

Acknowledging the age of the planet doesn't mean denying the existence of God. Just ask Dr. Francis Collins, the outspoken Christian geneticist who led the Human Genome Project and now heads the National Institutes of Health, the government organization that funds billions of dollars of biomedical research every year.

Collins has also set up the BioLogos Foundation, which "promotes the search for truth in both the natural and spiritual realms seeking harmony between these different perspectives."

In an interview with Christianity Today, Collins talked about the importance of Christians embracing science, even when it seems to conflict with theology.

"If you ask about data-driven questions, about what is true and what is the evidence to support it, you would want to go to the people who are the professionals who spend their lives trying to answer those questions and ask, 'Is there a consensus view?'" Collins said.

"So you ask, 'What is the age of the Earth?' Well, who does that work? It is the geologist and the cosmologists and the people who do radiocarbon dating. It is the fossil record people and so on," he said.

"So you ask, 'Is this an unanswered question?' And the answer you would get is that the issue is settled. The age of the Earth is 4.55 billion years."

Wouldn't it be refreshing if a member of the Senate science committee had that kind of regard for science?

It ought to be a requirement.