I didn't find out until January of this year and my wife and I have been married for 18 years so I can't give advice about when to disclose in the dating stage; however, my advice would be to disclose when you think things are starting to get serious. Or to put it another way, I think it's important for both of you to disclose before things get too far along.
I think it's only fair to your partner when the relationship becomes serious. I think they have a right to know. I firmly believe that. Imagine dating, getting serious, getting even more serious, perhaps thinking about marriage, getting married or living together.....then imagine not telling your partner during any of those stages after getting serious. How terrible would that be? If you did finally reveal, say years later, trust might take a hit or even be shattered depending on the relationship.
However, I don't think there's a need for you to disclose when you're dating initially in the stage when you may not go on subsequent dates. What would the point be? Think about all the other sensitive personal topics people share with each other when they end up getting serious. That stage is the time to disclose in my opinion.