When kids see adults reading they’re more likely to read, themselves. It isn’t just a theory, there’s been research done on this.
When a kid sees an adult reading a children’s book, he’s even more likely to read. Try picking up a kid’s book for yourself the next time you’re at the library; the effect on your child will be very interesting.
My literacy colleague, Jen Robinson, has a slew of other great reasons why adults should read children’s literature.