I had identical twin girls on February 29, 2008.  They were started on Enfamil Lipil in the hospital, and due to the high cost of having to buy twice as much formula with twins, I reluctantly asked my pediatrician about using Wal-mart's store brand Parent's choice instead of Enfamil.

After giving me all the free Enfamil that he could from his office, he told me that if we used the Parent's choice corresponding brand milk-based infant formula with iron, it would virtually be the same and would be acceptable to use.  He informed me that if the twins had any adverse side effects, to call him immediately. ...