He was writing jointly with the anti-gay Family Research Council president Tony Perkins for Politico magazine.
The pair wrote that homosexuality has "profound behavioural implications" and "inevitable" sexual attraction among soldiers could "devastate morale, foster heightened interpersonal tension and lead to division".
They added that an increased risk of HIV in gay and bisexual men would be "devastating" and have "pronounced implications for battlefield blood transfusions".
Quoting data from the Centers for Disease Control and Prevention, they said gay and bisexual men were "50 times more likely to have HIV than heterosexual men".
The wrote: "This proposal is not about bigotry. Race is a superficial and benign element of one’s humanness, while homosexuality is a matter of behaviour.
"Homosexuality is not about civil rights but conduct detrimental to the discipline, trust and combat readiness of what has been — and still is — the world’s finest military."
They concluded: "If we want to keep it that way, we should not permit openly practicing homosexuals to serve in the US military."
Gen Sheehan avoided a reprimand for his remarks at a Senate hearing on the military's ban on out gay soldiers.
He said that Dutch military officials told him that allowing gay soldiers the Dutch army had led to poor morale, which led to a failure to prevent the genocide of 8,000 Muslims.
He later wrote to Dutch officials to apologise for "inaccurately " remembering discussions.
Source: Pink News