Ensuring boys do not become more emasculated deserves an entire column in itself. Some ideas:
Throw away your son’s iPod, X-Box, video games, etc.; or ban them except for limited times on weekends, and never during the day in summer.
Get them involved in hard work outdoors — building fences, trail-clearing work (if teenagers), car maintenance, painting outdoors, etc. Boys WANT to be real guys but they need examples from their Dads or other trusted men.
Boy Scouts is great. But most boys outgrow it by 15, totally by 16. So try the local Civil Air Patrol squadron or the local Coast Guard Auxiliary. Both a quasi-military but there will be no shortage of decent men serving as role models, and the boys will get their hands dirty and be doing real work.
Talk to them about the differences between boys and girls and teach them to honor and respect women, first their Mom and sisters, then all others. Tell them to ignore what they hear in school, and on the Disney Channel.
Take them out off-road on ATVs or to the local indoor shooting or skeet range. Nothing makes a 12-15 year old feel “like a man” than when his Dad does such with him
= bad adult leadership. Properly planned, led, and delivered Boy Scout programs should develop boys into men with leadership skills all the way to age 18. Other posters have mentioned key elements: real work, outdoor challenge, leadership opportunities, etc. I say this from the perspective of former adult Scout leader (Scoutmaster, Committee Chair, District Roundtable, Philmont trek advisor) and father of an Eagle Scout. The other programs you mention have good male role models involved, I'm sure, but since I have experienced good Scouting, I am a firm believer.