The Church strongly discourages surrogate motherhood. If parents want a child who was born to a surrogate mother to be sealed to them, the stake president refers the matter to the Office of the First Presidency.
So, not only does the Church "strongly discourage" surrogate motherhood, but in order to have your brand new baby (born via a surrogate) be part of your eternal family, the highest LDS council must first say it's ok with them. I have no doubt the FP will approve this for Tagg and his wife, but I wonder if the FP ever says no to this request.
by the way, here's the link to the story about Tagg and his new sons:
http://thecaucus.blogs.nytimes.com/2012 ... surrogate/
Note in the article that the Church spokesman simply states that surrogate motherhood is "discouraged," while the CHI states it is "strongly discouraged." As I suspected, perhaps the Romneys do get special treatment.