N600k question on spouse

[arpad]

My fiancee is a US Citizen living in Brazil where she was born, and received her dual-citizenship status through her father, who still resides in the US. She has two minor kids, who we are trying to get citizenship for so that they can move to the US. Everything seems like it would work with the N600k, except I have a question about the spousal information.

The problem is that she was never officially married to the kids' father.
Brazil is a common-law country, and they were living together so they were married according to the common-law rules there, but they don't have any documentation to prove it. Therefore, they don't have any documentation that says they are not together anymore, either.

So I need to figure out if it's easier or advantageous to claim as if they were married and then divorced, or that she was never married.

Would the USCIS deny the application if the kids are illegitimate?

Any help is much appreciated!

 

[Jackolantern]

When the mother is a US citizen, not being married to the noncitizen father usually isn't a barrier to citizenship for the children.

http://travel.state.gov/law/info/info_609.html

Birth Abroad Out-of-Wedlock to a U.S. Citizen Mother: A child born abroad out-of-wedlock to a U.S. citizen mother may acquire U.S. citizenship under Section 301(g) INA, as made applicable by Section 309(c) INA if the mother was a U.S. citizen at the time of the child's birth, and if the mother had previously been physically present in the United States or one of its outlying possessions for a continuous period of one year.