Hello,
  Today I'm wondering about pitching in baseball. I specifically want
to know what types of effects pitching side-armed have, compared to
pitching the normal overhand style. I mean what types of tissue are
torn, what is the long term damage after pitching constantly with it?
Also, what is the age at which a Child can start throwing breaking
pitches[curveballs, sliders, slurves...] with no permanent damage?
Thank you very much.

Excellent questions. Seems that very few parents and coaches think
along these lines. Whether a young player has talent in any sport, it
is important that correct technique is taught, along with over all
conditioning. Parents are usually flattered to hear that their child
has talent and assume a coach has knowledge or skill to impart. That
may or may not be true. The majority of talented players in all sports
have incurred nerve, muscle and orthopedic damage from over use by
college age. The most common reason athletes drop a sport at any age
is over use at too early an age. Throwing a baseball pitch is one of
the most difficult skills in sports, requiring accuracy, velocity and
variety. All torque the elbow and shoulder and stress the back.

http://www.homestead.com/youthbaseball_e_zine/Pitching.html

http://www.keepkidshealthy.com/adolescent/adolescentproblems/sportsinjuries.html

http://www.physsportsmed.com/issues/1999/06_99/whiteside.htm

http://www.infosprts.com/baseball/3.htm

http://www.explosivepitching.com/

Sparta308 --

The dean of Major League pitching coaches is Lee Mazzone, of the
Atlanta Braves.  His "Pitch Like a Pro" is considered one of the
most-authoritative on pitching and the physical demands that spawn
injuries.  It's written for developing teenagers and Amazon.com has
the ability to look inside the book here:
http://www.amazon.com/gp/product/0312199465/104-8031811-3320732?v=glance&n=283155

Lots more attention has been paid in recent years to injuries,
particularly to pitchers.  It's one of the reasons that every team now
uses pitch counts to manage a game.  One of the writers who's
developed a focus on it is Will Carroll, who's written a column called
"Under the Knife" for years, and now writes for Baseball Prospectus. 
However, Carroll concentrates more on young professional players than
high school-levels:
http://www.baseballprospectus.com/news/?column=20

Best regards,

Omnivorous-GA