Calculate Date of Birth in SSRS
You can utilize this code in an Expression to find the Date of Birth.
=IIF(IsNothing(Fields!dateofbirth.Value), "",
IIF( ((Month(Now) - Month(Fields!dateofbirth.Value)) < 0)
OR ((Month(Now) - Month(Fields!dateofbirth.Value)) = 0
AND (Day(Now) - Day(Fields!dateofbirth.Value)) < 0),
(Year(Now) - Year(Fields!dateofbirth.Value)) - 1,
(Year(Now) - Year(Fields!dateofbirth.Value))
))