I've been thinking on this the past couple of days. John Locke and Benjamin both have a mother who was named Emily. Is there any possibility that they are the same woman and that these two are half brothers?
Locke was born to Emily Annabeth Locke on May 30, 1956.
Ben was born December 22 sometime in the mid to late 60's.
Locke's mother could have given birth to him, figured out the deadbeat Cooper and gave him up. (She also was known to have mental problems.) Maybe she met up with Roger a few years later and gave birth to Ben.

Now I realize that Locke's mother was supposedly still alive and contacted Locke a few years ago......basically steering him to his deadbeat scamming daddy. But do we know for a fact that that woman was indeed Emily Annabeth? Could she have been hired by Cooper...to run a scam on John? I do not know if this question has already been raised, if so I apologize. I am sure if there is no possible way this could be true you guys will know...

But is could be a cool twist....especially with the whole Bad Twin book angle.