Many martial arts put a lot of stress on dealing with an attacker—no not just dealing with, but utterly destroying or at least immobilizing them—through a heavy reliance on knees or kicks or grabbing to the groin.

Please be aware of the fact that in a street fight for your life with adrenalin pumping the fear through your body and the attacker's, a kick or knee to the groin is not the end-all it is made up to be.

I, and many other men, have been kicked and kneed to the groin in our training and heavy sparring with adrenalin pumping.

We have been kicked, poked, punched in the groin since we were 4 years old. Most of us have a built-in reflex to protect that area.

Ming chastising student

I have yet to fall down unconscious, discontinue my attack (remember, at Core JKD we train with purposeful intent, a focused mind and drive toward a goal), or curl up into a ball while my attacker stands over me with arms raised and a gleeful smile on his or her face.

I have felt pain from it. (Neck nerve trauma pain trumps it easily)

I have felt nauseated from it. (First wife trumped that. Honestly. She just had to go to that expensive restaurant where I got serious food poisoning.)

I have never not been able to continue defending myself or pushing through on my attack. 

And I have never seen another man in training unable to defend themselves because of a hard hit to the groin

Do not expect an attacker in the street to do otherwise.

Even though you may have been told men think with their smaller head, hitting it does not actually knock us out.