Parent got naturalized while minor child was abroad. can child re-enter using GC?

[prouddesi]

My minor child and I (mother) are visiting India (both Indian citizens). My child entered India using an Indian passport.
Meanwhile, my spouse (father of the minor child) had to attend the naturalization interview and later the oath. Has the child automatically become a citizen of the US now? Can the child enter back to the US with an Indian passport and GreenCard OR is a US passport mandatory?
If the child needs a US passport, what are the next steps to get those?

[flyingron]

Was the minor child listed on your husband's N-400?

[newacct]

My minor child and I (mother) are visiting India (both Indian citizens). My child entered India using an Indian passport.
Meanwhile, my spouse (father of the minor child) had to attend the naturalization interview and later the oath. Has the child automatically become a citizen of the US now? Can the child enter back to the US with an Indian passport and GreenCard OR is a US passport mandatory?
If the child needs a US passport, what are the next steps to get those?

I am not sure whether your child is considered to have become a US citizen when the father became a US citizen, or when the child comes back to the US. The text of INA 320 is here, and the page of the USCIS policy manual is here. It requires that the child be "residing in the United States" "pursuant to a lawful admission for permanent residence". I am not sure whether that can be met while the child is physically outside the US. I guess the child is still "residing" in the US if they are on a visit elsewhere.

In any case, there will almost certainly be no problem for the child to return on their green card. The immigration officers at entry don't have the time or information to adjudicate the complicated details of whether citizenship provisions were met. And even if they did, the child is either a permanent resident (who can enter on a green card) or a US citizen (who cannot be denied entry no matter what), so the child can enter either way.

[newacct]

Was the minor child listed on your husband's N-400?

Whether a child is "listed" on N-400 never makes any difference for the child's immigration or citizenship.