risk of the mission not being accomplished or males refusing to die for others since male bonding is the reason troops lay down their lives for friends. Russia in WWII and Israel in 1948 found that mixed combat units means a higher casualty rate as the males sacrifice their missions to protect the females and the enemy fights to the death rather than to be defeated by units with females in them. Russia's answer that worked was to have all female units and all male units. Lili Lutvak was an ace WWII Russian pilot but she had an all female team, even the mechanics being female.