Macro to insert row if cell(i,1) notequal cell(i,1)+1 and insert certain values in row.

Please use code tags in the future when posting codes.

Try this:

Sub macro1()
    Dim i As Long
    i = 3
    Do Until Trim(Cells(i, 1)) = "" Or Trim(Cells(i + 1, 1)) = ""
        If Cells(i + 1, 1).Value <> Cells(i, 1).Value + 1 Then
            Cells(i + 1, 1).EntireRow.Insert shift:=xlDown
            Cells(i + 1, 1) = Cells(i, 1) + 1
            Cells(i + 1, 2) = Cells(i, 2)
            Cells(i + 1, 3) = 0
        End If
        i = i + 1
    Loop
End Sub

Great, thank you so much for the super quick help, millz!!

The code works very well and without errors now! I edited it a little though, as it counted the years on to infinity, instead of starting after year 2011 again at 1969 for the next age class. In case somebody ever needs sth like this again, here the final version.

Sub macro1()
    Dim i As Long
    i = 3
    Do Until Trim(Cells(i, 1)) = "" Or Trim(Cells(i + 1, 1)) = ""
        If Cells(i + 1, 1).Value <> Cells(i, 1).Value + 1 Then
            If Cells(i, 1).Value = 2011 Then
                If Cells(i + 1, 1).Value <> 1969 Then
                Cells(i + 1, 1).EntireRow.Insert shift:=xlDown
                Cells(i + 1, 1) = 1969
                Cells(i + 1, 2) = Cells(i + 2, 2)
                Cells(i + 1, 3) = Cells(i + 2, 3)
                Cells(i + 1, 4) = Cells(i + 2, 4)
                Cells(i + 1, 5) = Cells(i + 2, 5)
                Cells(i + 1, 6) = 0
                End If
            Else: Cells(i + 1, 1).EntireRow.Insert shift:=xlDown
                Cells(i + 1, 1) = Cells(i, 1) + 1
                Cells(i + 1, 2) = Cells(i, 2)
                Cells(i + 1, 3) = Cells(i, 3)
                Cells(i + 1, 4) = Cells(i, 4)
                Cells(i + 1, 5) = Cells(i, 5)
                Cells(i + 1, 6) = 0
            End If
        End If
        i = i + 1
    Loop
End Sub