I really need some help here.

I have a table [family]arent_name, my_name

and I want to pass 'adam' as a parameter and get the number of family members
down 3 generations

the data would be:
god, adam
adam, Michael
Michael, Lucifer
adam, john
John, Matthew
Matthew, David
David, Peter
Peter, Paul
Paul, Wendy

so 'Adam' has 5 members (3 levels deep, john&michael&Lucifer&Matthew&David),
David and his offspring are ignored.

and cannot understand 'books online' so am pretty much completly stuck.
If anyone can help I would really appreciate it
thanks in advance