A child born out of wedlock. The father is a bachelor and is not dating or seeing the mother of the child.
Tom Brady is dating the supermodel Gisele Bundchen, but has a bachelor baby with Bridget Moynahan.

The NFL number one draft pick has three bachelor babies he has to support.
by B. Hanback January 25, 2008
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A "bachelor" party thrown for a father to be on the day of the expecting mothers's baby shower. Hall passes are rare in this world and get even more scarce after a baby so take advantage when you can.
My wife had her baby shower yesterday so my boys threw me a "Baby Bachelor Party" where we proceeded to d0 our best impression of "The Hangover"...
by Freeslouz March 27, 2011
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