In your company, who does (and who should) be responsible for unit-testing? [on hold]

As the title says, this is a question for all you professional developers in the business. TDD is a big thing right now, so my question is as follows:

Who does the unit-testing in your team? Is this the QA-s responsibility or the programmers? Who should do them?

In my opinion (I'm not a professional developer), I think the QA should do the unit-tests. They are responsible for testing, am I wrong?