[Beckwith]

Is the State Department a good enough source for you? http://travel.state.gov/law/citizenship/citizenship_776.html

There is no reference to “adoption” at your source.

[ReignOfError]

There is no reference to “adoption” at your source.

Parents cannot renounce U.S. citizenship on behalf of their minor children. There's no exception for adoptive parents.

[El Gato]

But there is also no exception for it. The requirements are:

B. ELEMENTS OF RENUNCIATION

A person wishing to renounce his or her U.S. citizenship must voluntarily and with intent to relinquish U.S. citizenship:

1. appear in person before a U.S. consular or diplomatic officer,
2.in a foreign country (normally at a U.S. Embassy or Consulate); and
3. sign an oath of renunciation
It also says:

F. RENUNCIATION FOR MINOR CHILDREN

Parents cannot renounce U.S. citizenship on behalf of their minor children. Before an oath of renunciation will be administered under Section 349(a)(5) of the INA, a person under the age of eighteen must convince a U.S. diplomatic or consular officer that he/she fully understands the nature and consequences of the oath of renunciation, is not subject to duress or undue influence, and is voluntarily seeking to renounce his/her U.S. citizenship.

But this is a bit incomplete, since there are other ways to renounce citizenship than making the application described above.

Here's The Law

Basically you can't until you are 18. P>