Blood may be thicker than water, but hate is thicker than blood. Just ask your boy Mark McGwire'the former home run king is about to be thrown under the his own brother. In an upcoming tell-all book, Jay McGwire details Mark's (alleged) steriod use and claims that he was the one to inspire Mark to begin 'roiding out (no way, Jose?). Damn, what happened to loyalty, fam?

Of course, Jay's brotherly betrayal isn't the first time we've seen family members rat on each other. Read on for the biggest family snitches of all-time...
NAME: Ted Kaczynski, a.k.a. The Unabomber (right)
BETRAYED BY: His brother, David Kaczynski
FAMILY FEUD: The FBI spent mad money but still failed to catch the Harvard-educated, PhD-toting, bomb-planting psychopath. But when David Kaczynski recognized his brother's writing in the Unabomber Manifesto, he quickly led authorities to Ted's cabin. You da bomb, Dave.

NAME: George Jung (portrayed in Blow by Johnny Depp)
FAMILY FEUD: George Jung grew up listening to his cash-craving mom complain about their destitute financial situation. So, logically'since he had no wicked jump shot'he started moving weight. In a weaksauce move, his mother decided his actions were just too illegal and called the cops on him. That's real fucked up, mom.

NAME: Michael Lohan
BETRAYED BY: His daughter, Lindsay
FAMILY FEUD: This past Christmas Eve, LiLo used her Myspace blog to air some dirty laundry: Her daddy Michael Lohan cheated on his wife and fathered an illegitimate child. Michael promptly accused SaMANtha Ronson of typing the message. Homophobe!

NAME: Fredo Corleone
BETRAYED BY: His brother, Michael
FAMILY FEUD: Blinded by greed and jealousy, Fredo Corleone helps gangster Jews in their attempt to assassinate his younger brother, Michael. They fail. Michael then orders his henchmen to kill Fredo. Later, while fishing, Fredo is reciting the Hail Mary when he is interrupted by a BULLET BULLET.

NAME: Joseph (and his Amazing Technicolor Dreamcoat)
BETRAYED BY: His brothers
FAMILY FEUD: "Brother will betray brother to death." So says Matthew 10:21, and starting with Cain and Abel, the Bible is filled with family betrayal. Our favorite is like the Old Testament version of getting run for your Jordans: When Joseph's mongrel brothers grow jealous over Joe's dope-ass jacket, they sell his ass straight into slavery. Joe later forgave them, but we wouldn't.