Well? It would have made sense now, wouldn't it.
Because they didn't...
err good answer - not
Oooooh good one
Only if they had 13 kids. But they have 12, so the title wouldn't make much sense in that regard. Also, the movie was based on the book about a family with 12 kids called "Cheaper by the Dozen," so the title was left as is.
no problem , just chuck an extra kid in