Ask YC: Who is a founder?

I'm heading a small startup that's looking to get funding. Despite our lack of money, I've managed to recruit a programmer, a finance person, and a marketing person; we're moving ahead with development and marketing plans, even as we look for angel or VC funding. I have a separate agreement with each team member, giving them options in the company as well as some compensation if we get funding but don't work together. I'm happy with all of the agreements we've reached to date.

It's pretty clear that we need a graphic designer. We think that we've found a good and talented one, and she seems inclined to join us, once we negotiate exact terms. But she has asked to be described as a "founder."

Now, I was developing the business idea, including market research and technical analysis, for about a year before anyone else joined me. It's clearly my vision, including my overall marketing plan and technical architecture -- although clearly, there's no way that I could have gotten as far as I have without the other (amazing) people I've recruited. But we've now been working together since October, including meetings with each other, VCs, and angels. None of the other people have asked to be called founders; as far as they're concerned, it's fine for me to be the only founder.

My question is this: Should I call this designer a founder? Would that mean calling everyone else, who has been working with me much longer, a founder as well? Or should I just keep things as they've been so far?

My gut feeling is to keep things as they are, with me as the only founder. But if it's typical for all of the pre-money people to be called founders, then I'm happy to share the title. I just want to know what's typically done, assuming that there is any typical case.