At first blush, it would appear that Brown is attempting to coddle to his religious Right base by doubting the "out of wedlock" status of his birth, though it is well documented that his mother was married at the time of his birth. But you'll notice at the end, he says that it's more important to focus on Obama's mother's age at the time - 18. So why are either of these important in the broader landscape of Obama as, at the time this clip aired, candidate for President? The answer is they aren't. This is almost a devalued concept as the original "birther" allegations.
Now, Brown is attempting to claim this is all fabricated by Martha Coakley:
He doesn’t believe that. This is more desperate campaigning from Martha Coakley. When she isn’t calling for higher taxes, she’s making things up about Scott Brown.
So if he doesn't believe it why did he say it? Sure, this was over a year ago and he may have changed his mind, but that doesn't change the fact that he said it to begin with with seemingly no validation. What does Obama's mother's age at the time of his birth have to do with his ability to hold higher office?