ᎣᏂ ᏧᏩᎫᏛ ᎯᎠ ᏗᎦᏘᎸᏍᏗ, ᏧᏓᎴᏅᏓ ᎠᏟᎶᏍᏙᏗ theories ᎤᎭ emerged. ᎾᏍᎩ ᎯᎠ ᎠᏠᏯᏍᏛ ᎤᏝᏅᏓᏕᎲ Ꮎ ᏗᏂᏏᏴᏫᎭ ᎭᏫᎾᏗᏢ ᎯᎠ ᎠᎹᏰᏟ ᎠᏰᎵ ᎤᏙᏢᏒ ᎤᎾᏛᎩ ᎯᎠ ᎤᏩᎫᏗᏗᏒ ᏗᎦᏘᎸᏍᏗ ᎠᎴ ᎤᏄᎸᏅᎩ ᎢᏯᏛᏁᎯ ᎾᎿ Ꮎ ᎥᎦᏔᎲᎢ, ᎠᎴ Ꮎ ᎤᏅᏌ ᎤᏙᎯᏳᎯᏯ ᎠᏟᎶᏍᏙᏗ ᎯᎠ ᏗᎦᏘᎸᏍᏗ. ᎠᏟᎶᏍᏙᏗ theorists ᎤᎭ ᎠᏆᏤᎵ ᎤᏛᏅᎩ Ꮎ ᎯᎠ ᏰᎵ ᏄᎵᏂᎬᎬᎾ ᎯᎠ ᎡᎶᎯ ᏗᏓᏁᏟᏴᎡᏗ ᎠᏰᎵ ᏥᏄᏍᏛᎩ ᎢᎬᏂᏌᏅᎯ ᎾᎥᎢ ᎠᎾᎵᏖᎸᎲᏍᎬ ᎦᏁᏰᎩ. ᎢᎦᏛ ᎾᏍᎩ ᎾᏍᏇ ᎠᏥᎡᏗᏱ Ꮎ ᎠᏓᎾᏅᏗ airliner ᏄᏛᏁᎸ ᎾᏍᎩ ᏂᎨᏒᎾ ᎤᏲᏨᎯ ᎾᎾᎯ ᎯᎠ ᏓᏍᏓᏅᏅ ᏚᎷᏨ, ᎠᎴ Ꮎ [[United Airlines Flight 93|ᎠᏫᏒᏗ Airlines ᎤᎳᏫᏛᏓ 93].] ᏥᏄᏍᏛᎩ ᏗᏍᏓᏲᏍᏗ ᎡᎳᏗ.

ᎡᏍᎦᏂ ᎾᎿ ᎯᎠ ᏴᏫ ᎠᏰᎸ Ꮎ ᎤᏙᎷᏬᏗ ᎤᎵᏍᏛ ᎤᏍᏗᏰᎬ ᎤᏛᏏᏗᏒ ᎤᏍᏆᎸᎲ ᎠᎵᏌᎳᏗᏍᎬ androgens ᎭᏫᎾᏗᏢ ᎢᏧᎳ sexes, ᎠᏂᏍᎦᏯ ᎠᎴ ᎠᏂᎨᏴ, ᎠᎴ ᎯᎠ underarms ᎠᎴ ᎯᎠ pubic ᎡᏍᎦᏂ. ᎭᏫᎾᏗᏢ ᏧᏓᎴᎾᎢ, ᏄᎶᏒᏍᏛᎾ ᎾᏍᎩ ᎤᏩᏒ ᎠᏂᏍᎦᏯ ᎠᏛᏍᎬ androgenic ᎤᏍᏗᏰᎬ ᎭᏫᎾᏗᏢ ᏐᎢ ᎡᏍᎦᏂ. ᎾᎿᎢ ᎨᏒᎢ sexual dimorphism ᎭᏫᎾᏗᏢ ᎯᎠ ᎢᎦᎢ ᎨᏒ ᎠᎴ ᏗᏗᎦᎴᏴ androgenic ᎤᏍᏗᏰᎬ, ᎬᏙᏗ ᎠᏍᎦᏯ ᎤᎲᎢ ᎤᏟ ᎢᎦᎢ ᎤᎵᏍᏛ ᎤᏍᏗᏰᎬ (ᎾᏍᎩᎾ ᎨᏒ facial ᎤᏍᏗᏰᎬ, ᎦᏁᏥ ᎤᏍᏗᏰᎬ, ᎭᏫᎾᏗᏢ ᎤᏍᏗᏰᎬ ᎠᎴ ᎤᏍᏗᏰᎬ ᎾᎿ ᏗᏂᏅᏍᎨᏂ ᎠᎴ ᎧᏃᎨᏂ) ᎠᎴ ᎠᎨᏴ ᎤᎲᎢ ᎤᏟ ᎢᎦᎢ vellus ᎤᏍᏗᏰᎬ, ᎦᏙ ᎤᏍᏗ ᎨᏒᎢ ᎦᏲᎵᎨ ᎬᎪᏩᏛᏗ. ᎯᎠ genetic ᏚᏂᏲᏍᎬ ᏗᎫᎪᏙᏗ ᎯᎠ ᏧᏠᎯᏍᏗ-ᎦᏛᎢ ᎠᎴ ᎠᏂᏏᏴᏫᎭ ᎠᎵᏌᎳᏗᏍᎬ androgens ᎠᎴ ᎾᏍᎩ ᎢᎬᏂᏏᏍᎩ ᎯᎠ ᏚᏙᎳᏩᏛᎲ androgenic ᎤᏍᏗᏰᎬ.

ᎯᎠ ᏗᎦᏘᎸᏍᏗ ᎾᎿ ᏓᎬᎾ ᏥᏳ ᏗᏔᎳᏗᏍᏗ ᎠᎴ ᎯᎠ ensuing ᏓᏄᏩ ᎭᏫᎾᏗᏢ ᎯᎠ ᎡᎷᏪᎢ, fueled anti-ᏣᏩᏂᏏ ᏴᏫ ᎾᏁᎵᏍᎬ. ᎠᏂᏣᏩᏂᏏ, ᎠᎹᏰᏟ-ᎠᏂᏣᏩᏂᏏ ᎠᎴ ᎠᏂᏓᎶᏂᎦᏍᏛ ᎤᎲᎢ ᎤᏠᏱ ᏄᎵᏂᎬᎬ ᎦᎾᏄᎪᏨᎢ ᎨᏒᎩ ᎾᏍᎩ ᎠᏰᎸᏅ ᎬᏙᏗ ᎦᎳᏩᏎᏗ, ᎾᎪᎯᏳᎲᏍᎬᎾ ᎠᎴ ᎠᏓᎾᏆᏘᏍᏗ. ᎯᎠ ᏗᎦᏘᎸᏍᏗ ᏥᏄᏍᏛᎩ viewed ᏥᏄᏍᏗ ᎤᎲᎢ ᏭᏪᏙᎢ ᎾᏛᏁᎲᎩ ᎭᏫᎾᏗᏢ underhanded ᎦᎶᎯᏍᏗ ᎠᎴ ᎾᏍᎩ ᎾᏍᏇ ᏥᏄᏍᏗ ᎤᏙᎯᏳ ""ᎤᏕᎰᎯᏍᏗ"" ᎠᎴ ""sneaky ᏗᎦᏘᎸᏍᏗ"". ᎯᎠ ᎤᎾᏰᎯᏍᏗ Japanese-ᏴᏩᏁᎬ ᎯᏍᎩᏁ ᎤᏓᏅᏅ ᎤᏗᏅᏒᎩ ᎯᎠ ᏂᎬᎢ ᎠᏓᏂᏴᏗ ᎪᎯ ᎦᎵᏓᏍᏛ ᎾᏂᎥ ᏴᏫ ᎣᏂ ᏧᏩᎫᏛ ᎧᎦᎵ 19, 1942 ᎠᎴ Ꮝ ᏄᎵᏍᏔᏅ ᏣᏩᏂᏏ-ᎠᎹᏰᏟ internment, ᏄᏢᏉᏛᎾ ᎠᎴᏂᏍᎬ ᏫᏚᏳᎪᏛ ᎦᏅᏍᏙᎯᏍᏗ ""ᎤᏓᏂᏝᏅ ᎠᎴᏫᏍᏙᏗ"", ᎭᏫᎾᏗᏢ ᎢᏧᎳ ᎯᎠ ᏣᏩᏂᏏ-ᎠᎹᏰᏟ internment ᎠᎴ [[Japanese|ᏣᏩᏂᏏ-Canadian internment.

ᎠᏤᎸᏗᏱ, 27 ᎠᏁᎳ Al-Qaeda ᎠᏁᎳᏛᏅ ᎠᏴᏍᏗ ᎯᎠ ᎠᏫᏒᏗ ᎧᏃᎮᎭ ᎠᎩᏍᏗ ᎢᎦᏛ ᎭᏫᎾᏗᏢ ᎯᎠ ᏚᎵᏍᏗ 11 ᏗᎦᏘᎸᏍᏗ. ᎭᏫᎾᏗᏢ ᎯᎠ ᎤᎵᏍᏛ, ᎾᏍᎩ ᎤᏩᏒ 19 ᎠᏤᎸᏗᏱ participated. ᏐᎢ ᏯᏓᎢᏗᏏ-ᎾᏍᏋ hijackers ᎠᎴ ᎢᏳᏓᎵᎭ ᏩᏎᎸᎯ ᏥᏄᏍᏗ ᎯᎠ 20th hijacker:

ᎯᎠ ᎬᎾᏕᎾ ᎠᏂᎧᎻᏏᏂ ᎾᎿ ᎠᏓᎯᏍᏗ ᏗᎦᏘᎸᏍᏗ ᎾᏍᎩ ᎯᎠ ᎠᏫᏒᏗ ᎧᏃᎮᎭ ᏥᏄᏍᏛᎩ ᎪᏢᎯ Ꭲgotlvhi ignelvhi ᎾᎥᎢ ᎯᎠ ᎠᏫᏒᏗ ᎧᏃᎮᎭ ᎠᏰᎵ ᎤᏙᏢᏒ ᎠᎴ ᏥᏄᏍᏛᎩ ᏱᏓᏟᎶᏍᏔᏅ ᎤᏯᏅᎲ ᎯᎠ 9/11 ᎠᏂᎧᎻᏏᏂ. ᎾᏍᎩ ᏓᏥᏲᏒᎩ Ꮝ ᎬᏂᎨᏒ ᎢᎬᏁᏗ ᎾᎿ ᎫᏰᏉᏂ 22, 2004, ᎠᏍᏆᏙᏅ Ꮎ ᎯᎠ ᏗᎦᏘᎸᏍᏗ ᎨᏒᎩ ᏁᎭ ᎠᎴ implemented ᎾᎥᎢ ᎠᏁᎳ Al-Qaeda. ᎯᎠ ᎠᏂᎧᎻᏏᏂ ᎤᏃᎮᎸᎩ Ꮎ, ""9/11 plotters ᏭᎵᏱᎶᎸ ᎤᏂᏩᏒ ᎾᎿ ᎯᎸᏢ ᎠᏰᎵ $400,000 ᎠᎴ $500,000 ᎠᏟᎶᏍᏙᏗ ᎠᎴ ᎾᏛᏁᎲ ᎤᎾᏤᎵ ᏗᎦᏘᎸᏍᏗ,"" ᎠᎴ Ꮎ ᎯᎠ ᏗᎪᏍᎩ ᎠᏓᎴᏂᏍᎬ ᎯᎠ ᎠᏰᎵ ᏕᎠᎲ ᎬᏔᏅᎯ ᎠᏍᏓᏩᏛᏍᏗ ᎢᏯᏛᏁᏗ ᎯᎠ ᏗᎦᏘᎸᏍᏗ ᏂᎦᏰᏙᎲᏊ ᎤᎧᏁᎳ. ᎢᏳ ᎢᎪᎯ, ᎾᏍᎩ ᎤᏩᏒ peripheral ᏗᏎᏍᏗ ᎤᎭ ᏭᏪᏙᎢ ᎠᏁᎶᏔᏅ ᎠᎴ Ꮭ ᎠᏰᎸᏗ ᎭᏫᎾᏗᏢ ᏗᎵᎪᏔᏅᎯ ᎬᏙᏗ ᎯᎠ ᏗᎦᏘᎸᏍᏗ.

ᎯᎠ ᎧᏅᏩᏅᎯ ᎾᏍᎩ ᎯᎠ ᎢᏳᏓᎵᎭ ᏗᏂᏏᏴᏫᎭ ᎠᎾᏍᎬᏘ ᏧᏓᎴᎾᎯ ᏂᏛᎴᏅᏓ ᎤᎾᏓᏟᏌᎲ ᎤᎾᏓᏟᏌᎲ, ᎢᏧᎳᎭ ᎭᏫᏂᏗᏢ ᎯᎠ ᎤᏠᏱ ᎢᏧᎳᎭ ᏗᏂᏱᎴᎩ. ᎾᏍᎩᎾᎢ ᏱᏓᏟᎶᏍᏔᏅ, ᏌᏊ ᏯᏛᎿ ᎠᏂᏏᏴᏫᎭ ᎠᎾᏍᎬᏘ ᎠᎩᏍᏗ ᎤᏤᎵᏛ ᎧᏅᏩᏅᎯ, ᎠᎦᏎᏍᏙᏗ, ᎠᎴ ᎠᎦᏎᏍᏙᏗ ᏂᏛᎴᏅᏓ ᎯᎠ ᎠᏂᏐᎢ ᎭᏫᎾᏗᏢ Ꮝ ᎤᎾᏓᏟᏌᎲ, ᎾᎯᏳᎢ ᏄᏓᎴ ᎤᎾᏓᏟᏌᎲ ᎯᎠ ᎤᏠᏱ ᎢᏧᎳᎭ ᏗᏂᏱᎴᎩ ᏄᎵᏂᎬᎬ ᎧᏃᎯᏯᏍᏗ ᏯᏛᎿ ᏗᏂᏏᏴᏫᎭ, forcing ᎠᏂ ᎤᎵᏍᏕᎸᏗ ᎾᏍᎩᎾᎢ ᎤᏅᏌ. ᎯᎠ ᎠᏓᏅᏖᏗ ᎾᏍᎩᎾᎢ ᏯᏛᎿ behaviors, ᎠᎴ ᎦᏙᏃ ᎾᏍᎩ ᎯᎠ behaviors ᏧᏓᎴᎾᎯ ᏥᏄᏍᏗ ᎤᏅᏌ ᎿᏛᎦ, ᎤᎭ ᎩᎳ ᎾᏍᏋ ᎤᎦᏎᏍᏔᏅᎩ.