Syntax Error UGH!

This is a simple error but for some reason i've been staring at it for 30 mins and still can't seem to find whats wrong!! If someone can help that would be greatly appreciated. i'm getting the error:

Msg 102, Level 15, State 1, Procedure LibraryAddAdult, Line 12
Incorrect syntax near '('.
THERE IS NO ( NEAR LINE 12!

USE Library
GO

CREATE PROC LibraryAddAdult
@firstname shortstring,
@lastname shortstring,
@street shortstring,
@city shortstring,
@state statecode,
@zip zipcode,
@member_no member_no,
@middleinitial letter = ' ',
@phone_no phonenumber = ' ',
@expr_date datetime = dateadd(year, 1, getdate())

OUTPUT
AS
IF (
(@firstname = ' ') OR
(@lastname = ' ') OR
(@street = ' ') OR
(@city = ' ') OR
(@state = ' ') OR
(@zip = ' ') OR
(@member_no = ' ')
)
RETURN SELECT 'You must insert appropriate name, street, city, state, zip'


INSERT INTO member(firstname, lastname, middleinitial)
VALUES (@firstname, @lastname, @middleinitial)

INSERT INTO adult(street, city, state, zip, phone_no, expr_date)
VALUES (@street, @city, @state, @zip, @phone_no, @expr_date)

SET @member_no = SCOPE_IDENTITY()

RETURN
SELECT 'Member has been successfully added to the database'
SELECT (lastname + ' ' + middleinitial + ' ' + lastname) AS Name, street, city, state, zip, phone, expr_date
FROM member
INNER JOIN adult
ON member.member_no = adult.member_no