So......WHY do Democrats push for single parenting and "gay marriage"?

Simple: the children.

http://opinionator.blogs.nytimes.com/2014/02/08/how-single-motherhood-hurts-kids/?_php=true&_type=blogs&_r=0

http://www.frc.org/issuebrief/new-study-on-homosexual-parents-tops-all-previous-research