subsidizing
“One could also make the economic case that, with their taxes, childless couples are selflessly subsidizing the education and well-being of other people’s children (who provide tax breaks for their parents). Conversely, it is these parents’ descendants who will be taking care of the childless adults — and keeping society operational — when they are elderly.”
1 in this context, the "subsidizing"meaning ?
2 "who provide tax breaks for their parents" in U.S.,i'm wondering the meaning of "tax break "?
No Kids for Me, Thanks
http://www.nytimes.com/2015/04/05/style/no-kids-for-me-thanks.html
via Instapaper

Question

subsidizing
“One could also make the economic case that, with their taxes, childless couples are selflessly subsidizing the education and well-being of other people’s children (who provide tax breaks for their parents). Conversely, it is these parents’ descendants who will be taking care of the childless adults — and keeping society operational — when they are elderly.”
1 in this context, the "subsidizing"meaning ?
2 "who provide tax breaks for their parents" in U.S.,i'm wondering the meaning of "tax break "? 
No Kids for Me, Thanks
http://www.nytimes.com/2015/04/05/style/no-kids-for-me-thanks.html
via Instapaper

Answer

1- "subsidizing" means supporting or contributing with a part to the other children education and well being (for childless couples who are giving leaving more opportunities for other children)
2- "tax break" which is same as "tax cut", is when your taxes are reduced for some reason, and in this case for parents who have children, they get lower taxes.