DataSource Controls :: How To Hyphens In Field Data

Once again, I find myself stuck!

I am attempting to compare one of ASP.NET's membership userID's with the current userID in an SQL query, however because of the "hyphens -" in the uniqueidentifier field type of userID, i am unable to compare the ids. is there a way around this? (in my example, family_id from tblFamily is the userID that has type uniqueidentifier). my code as it stands is:

Dim UserID As String = New String(Membership.GetUser(User.Identity.Name).ProviderUserKey.ToString())
Response.Write(UserID)
Dim strConn As String = ConfigurationManager.ConnectionStrings("ApplicationServices").ConnectionString
Dim SQLI As New Data.SqlClient.SqlCommand("SELECT family_name FROM tblFamily WHERE [family_id] IS " & UserID & "")
Dim sqlCon As New Data.SqlClient.SqlConnection(strConn)
sqlCon.Open()
SQLI.Connection = sqlCon
Dim RSI As Data.SqlClient.SqlDataReader = SQLI.ExecuteReader()
RSI.Read()
Dim FamilyName As String = "0"
While RSI.Read
FamilyName = Convert.ToString(RSI("family_name"))
End While
Response.Write(FamilyName)
RSI.Close()
sqlCon.Close()