Why Do Women's Underwear Have Pockets?

I don't know why I wondered this...but I did.

Have you ever noticed? Not every pair of my underwear has a pocket...but a lot of them do!

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So...why the hell is that there?

There are a few answers out there. I'm not sure which to believe:

that it saves time and money to NOT sew that last bit of fabric
the material was added to make sure the underwear passes safety test (?)
if they DID sew the flap closed, the stitching would be irritating to your lady parts
where else ya gonna hide that lucky penny?

Okay, that last one was NOT found on the internet as a reason why - but maybe it should be added?

I have never really questioned the ol' crotch pocket, until recently. Do men have a 'pocket'? Is it special just for us?

Why is it only on some underwear?

Okay...problem of the day - it's up to you to tell me what the hell is happening?