Should they mix?
At the Olympics lots of the athletes from Usain Bolt down have been openly blessing themselves before events.
Lots of them have also offered a small prayer afterwards or have thanked God for doing well, or simply for taking part.
Mostly they haven't done so directly to camera or mentioned their religion in interviews afterwards. It's just something they do naturally and unaffectedly.
Religion is simply part of who they are, an integral part of their lives, like their families and friends.
Katie Taylor is completely open about her religion. After winning her semi-final on Wednesday she said: "It was a great win. An Olympic final tomorrow, what can I say. God is great. He is my shield, my strength. Glory to God. I have to go and be focused for tomorrow and forget about today. It's a different fight altogether."
But she didn't say this in a cloying or pious or Holy Joe kind of way. Religion is as natural to her as breathing.
It will still have been too much for some people. When Brazil won the World Cup in 2002, a few of the players whipped off their shirts to reveal T-shirts underneath emblazoned with the words, 'Jesus loves you'.
One sports writer didn't like this at all. He reckoned sports people should never, ever display their religion in public. He was as prudish about it as a Victorian maiden aunt might have been about someone mentioning sex in her company.
In fact, a lot of us have become prudish about religion in the way earlier generations were about sex.
We don't want anyone ever mentioning the subject around us, except to attack it.
Is what these athletes are doing equivalent to mixing sports and politics?
It would only be so if an athlete used the platform given to them by the Olympics to directly try and convert people to their faith, or attacked someone else's faith or lack thereof.
But none of the Olympic athletes I'm aware of has done that to date. They've simply thanked God before and after their events in the same way they might publicly thank their coach.
They thank him because they believe he should be thanked.
What is Katie Taylor's religion anyway? We've heard she's a 'born-again Christian', but most of us will only have the foggiest notion of what this actually is.
We associate 'born-again Christianity' with America, or maybe Northern Ireland and therefore it has mostly negative connotations for us.
We associate it with the wider fringes of the US Republican party and with fundamentalism and a completely literal interpretation of the Bible, that is, with a literal belief that God created the world in seven days only a few thousand years ago.
In fact, 'born-again Christian' Christians take their name from the New Testament and especially the passage where Jesus tells his followers "I tell you, no one can see the kingdom of God without being born again'.
'Born again Christians' believe you're only born again when you have a direct conversion experience and you fully and consciously commit your life to Christ.
'Born again Christians' are also called 'evangelical Christians' and that term is just as loaded as 'born again Christianity'.
But if you walked into a typical evangelical Christian church what could you expect to find?
For starters, there would almost certainly be a lot more singing (maybe of the 'happy-clappy' variety) than in a Catholic Church and the whole congregation would be taking part in the singing.
There would be a lot less ritual and a strong emphasis on the Bible and preaching from the Bible.
The preaching can be surprisingly good.
But what evangelical Christians do above all else is strongly emphasise the person of Jesus, in contrast to Catholics who often overemphasise the Church itself.
The result of this is that when many people think of Catholicism the first thing that comes to mind is the institution, not Jesus.
That's disastrous. It would be a bit like thinking of the FAI whenever we think of soccer.
Soccer is about the game, not the governing body.
Likewise, Christianity is supposed to be about Jesus and trying to live like him. If people thought of Jesus first and foremost when they think of Christianity, and not its governing bodies, it would be in much better shape than it is.
Admittedly, evangelical Christianity does have its fundamentalist tendency and that has often given it a bad name.
But at its best, evangelical Christianity boils Christianity down to its core and presents people directly with the figure of Jesus and invites them into a personal relationship with him.
This is why Katie Taylor speaks about her religion in a very personal and immediate manner that is unfamiliar to most Catholics, and ex-Catholics for that matter.
But it comes naturally to her.
It's part and parcel of who she is.