Hi,
No such rule, Sky. I'm Catholic and attended 12 years of Catholic education. In fact, I have two nuns in my family! Part of the curriculum was a requirement to study other faiths. Now, that doesn't make me an expert on ANY of the religions. I was more interested in hiking up my plaid uniform skirt!
In all seriousness, I would think her teaching credentials would be more of a consideration than her personal belief system.
Okie