Gabriel Arana has an article on DADT:
Gay and lesbian study participants who were asked to conceal their sexual orientation performed 20% worse on spatial reasoning tests and 50% worse on physical endurance tests as compared to those who were not given this instruction. The findings have clear implications for the battlefield. Gays and lesbians — even those who follow the policy — are prevented from performing optimally, which may affect the readiness of military units.
Bonus blog post here.
The Dish 