Bruce Jenner is seen as he sits down with ABC News anchor Diane Sawyer for a two-hour interview that aired during a special edition of ABC News’ “20/20" on Friday. (REUTERS/ABC News/Handout via Reuters)

The biggest shock to many during Bruce Jenner's Friday interview with ABC wasn't that he was transgender -- there have been rumors he would reveal that since February -- but that he was also a conservative Republican.

That didn't come as a complete surprise to anyone who's kept up with the Kardashian-Jenner politics. At the 2012 White House Correspondents' Dinner, Kim Kardashian said her parents were Republicans. She also described herself a Democrat who was impressed with "Rick Santoro" [sic] at the dinner, but then she described herself as a "liberal Republican" in an interview with The Guardian published four months later. So figure that out.

Among LGBT Americans, being Republican is much less common than being a Democrat, 21 percent to 63 percent. And given Jenner's status as a transgender American, his GOP politics struck many as surprising.

[Bruce Jenner said he's a Republican. Only 21 percent of LGBT Americans are.]

But in another key way, it's not really all that surprising. Jenner, who won the Olympic gold medal in decathlon in 1976, is also an athlete, a group that -- all indications suggest -- is more likely to lean conservative than other celebrities.

Look no further than Jenner's fellow American decathletes. Dave Johnson, who won the bronze medal in decathlon in 1992, said in an e-mail he is also Republican. And Bryan Clay, who won the gold medal in decathlon in 2008, spoke at the Republican National Convention that year.

There's no good, definitive polling data on athletes' political beliefs, but a poll of students conducted by the Brown Daily Herald at Brown University just this month found its student-athletes were more likely than non-student-athletes to hold conservative social and fiscal views.

Anecdotally, Charles Barkley has considered running for Alabama governor as a Republican and said he likes Chris Christie and Jeb Bush. Mitt Romney in 2012 was endorsed by John Elway, and a group of Olympians spoke at the Republican National Convention for the former head honcho of the Salt Lake City Olympics. Troy Aikman donated to Texas Gov. Greg Abbott's (R) campaign last year. Rep. Jack Kemp (R-N.Y.) was a professional football player before he was a member of Congress and Bob Dole's vice presidential running mate in 1996. Rep. Jim Ryun (R-Kan.) was the first high schooler to run a sub-four-minute mile and later ran in the Olympics. Shaq endorsed Chris Christie's reelection. And Maryland Republicans once tried drafting Cal Ripken Jr., for governor.

In the 2007 book "Next Man Up: A Year Behind the Lines in Today's NFL," John Feinstein wrote most Baltimore Ravens players were "either neutral, not interested, or Republican, like many Americans in the upper tax brackets. ... Most professional athletes aren't even registered to vote. Those who are almost always vote Republican."

There are plenty of Democratic athletes too, of course, but it often seems only inasmuch as there are Republicans in Hollywood; they exist, but they aren't as visible or vocal.

As Dean Rader wrote for the San Francisco Chronicle in 2011, it might be because the two fields attract a certain type of person. Actors, writers and producers deal in nuance, emotion, and contradiction, while athletes inhabit a world of meritocracy and hierarchy.

"To be successful in sports, there can be no gray areas," Rader wrote. "Complexity, contradiction, and uncertainty are the death of athletes. Thus, like in the military and the church, the world gets broken down into neat binarisms -- good/bad, winners/loser, white/black, wright/wrong. Those who see the world in this way, tend to affiliate with conservative principles."

A person's political beliefs can be complicated. They're informed by upbringing, geography, age, race, religion and gender. Jenner is transgender, but he's also, as Grover Norquist tweeted Monday, a "Reagan Republican."

Jenner might not fit the mold when it comes to the politics of the nearly two-thirds of LGBT Americans, but considering his background as an Olympic athlete, his views aren't all that surprising.

It's far too easy to typecast a person's politics based on their gender or sexual orientation. And Jenner is proof of that.

Note: Bruce Jenner's current name and a male pronoun is used in this post, as he has not requested a new name or pronoun be used.