Testicular Torsion is most frequent among adolescents with about 65% of cases presenting between 12 – 18 years of age, (ref). Immediate intervention is required in order to save the testicle. If ignored or delayed, the testicle can/will die! Governmental websites recommend Athletic Supporters for boys for all athletic or strenuous activity, and cups whenever a projectile is involved, whether that's a ball, foot, elbow or knee.(ref)
Testicular Trauma is any blunt force to the Testicles, and not only causes severe pain, but also embarrassment, can cause bruising or lead to other injuries.
Testicular Rupture is the actual erupting of a testicle. At that point, surgery must take place immediately.
Any of these can cause infertility, reduced sperm count and severe pain and embarrassment.
All of these injuries can be reduced, if not prevented entirely, by having your boys wear suitable protection.(ref)