Don't have an opinion on any of this, but how many of the population you calculate are citizens over the age of 18? And what would be saved from the US budget by eliminating various existing programs that would be superfluous by UBI?
Is there a risk here that the more vulnerable members of society will end up receiving less money?
http://www.amazon.com/The-Two-Income-Trap-Middle-Class-Paren...
As a side note, will a poor person who is unable to have a child be allowed to adopt and receive an increase in basic income, and will the adoption process by significantly more discriminating in who is allowed to adopt compared to who is allowed to have children?