By signing the Don't Ask Don't Tell Repeal Act of 2010, Obama fulfilled one of his a major campaign promises.
However, the Washington Post is reporting that unnamed Republicans have filed an amendment to a sweeping defense spending bill that would require all four military service chiefs to OK the new policy.
One of them, Marine Corps Gen. James Amos, has been strongly against the repeal of "Don't Ask, Don't Tell."
In signing the repeal, Obama said it would strengthen national security and uphold ideals.
The new law ends the 17-year-old "Don't Ask, Don't Tell" policy that forced gays to hide their sexual orientation or face dismissal. More than 13,500 people were discharged under the policy.
The change won't be immediate, however. The bill requires the military service chiefs to complete implementation plans before lifting the old "Don't Ask, Don't Tell" policy - and certify to lawmakers that it won't damage combat readiness, as critics charge
The Associated Press contributed to this report.