NOT when you open up a business. Then you follow secular law.
Well that's too bad for you. Because we are going do business, and we will not follow your secular laws on this matter.
So now what?
No, it's too bad for you, because you will be sued and probably go out of business. Then I suppose you would be here, crying.

Waaa, the government won't allow me to discriminate against the people I don't like!!! *stomps feet, takes ball and goes home*
No, not likely. Memorize Pizza collected over a million. Sweet Cakes collected over $300,000 (so far).
And they are both still in business, and continue to practice their faith.
If I go out of business, I'll just start up somewhere else.
Years ago in my parents church, there were a couple that decided to rent out an apartment over their garage. However, they decided they only wanted committed Christians in their apartment. Specifically boys and girls going to Christian colleges.
They rant that ad in the paper for years. Then some pagans complained (because the rent was really cheap). They ignored them until lawyers got involved.
Did they stop renting it out to Christians only? Nope. They just circulated the ads in Christian fliers, and churches, and Christian publications.
They never stopped practicing their faith up to the day they went home to be with the Lord.
You can't stop us darling. You never will.
Like I said... Christians have been dying for their faith for thousands of years. Your little law suits, and little fines, and such.... not a problem. We will handle that, and far more.