The age of two is the age Pim Diffy made Lloyd Diffy, when she was messing with the New Ager.
"He [Lloyd Diffy] got fired for telling his boss he made a `poopie`" -Phil Diffy to Keely Teslow
Max Joseph Tuber played two-year-old Lloyd.
A two-year-old Phil was, also, seen in a flashback of Halloween.
"...a toddler..."
-Phil Diffy explaining Halloween in the future