Hi Excel forum users!

I have the following code:
If Range("M10:M" & Cells(Rows.Count, 2).End(xlUp).Row).Value = "mom" Then
    Sheets("Sheet2").Range("L10:L" & Cells(Rows.Count, 2).End(xlUp).Row).ClearContents
    Sheets("Sheet2").Range("L10:L" & Cells(Rows.Count, 2).End(xlUp).Row).Select
    Set rng = Range(("L10:L" & Cells(Rows.Count, 2).End(xlUp).Row))
    With Selection.Validation
        .Delete
    .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:="=Sheet6!$A$1:$A$18"
    .IgnoreBlank = True
    .InCellDropdown = True
    .InputTitle = ""
    .ErrorTitle = ""
    .ErrorMessage = ""
    .ShowInput = True
    .ShowError = True
End With
Else
Range("M10:M" & Cells(Rows.Count, 2).End(xlUp).Row).Value = "dad"
Sheets("Sheet2").Range("L10:L" & Cells(Rows.Count, 2).End(xlUp).Row).ClearContents
    Sheets("Sheet2").Range("L10:L" & Cells(Rows.Count, 2).End(xlUp).Row).Select
    Set rng = Range(("L10:L" & Cells(Rows.Count, 2).End(xlUp).Row))
    With Selection.Validation
        .Delete
    .Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Operator:=xlBetween, Formula1:="=Sheet6!$A$19:$A$29"
    .IgnoreBlank = True
    .InCellDropdown = True
    .InputTitle = ""
    .ErrorTitle = ""
    .ErrorMessage = ""
    .ShowInput = True
    .ShowError = True
End With
End If
In the Columns M10:M I have 2 values: "MOM" and "DAD"
I try to use to fill with xlValidateList depending the values, but say me in excel erro that "Error: 13: "type MISTMATCH"

Please help!
Best Regards!!