Incluir varios TCheckBox en un TStringGrid.

var  X, Y: Integer;
cb: TCheckBox;
for X := 3 to 8 do
  for Y := 3 to 8 do
  begin
    cb := TCheckBox.Create(Self);
    cb.Parent := StringGrid1;
    cb.SetBounds(StringGrid1.CellRect(X, Y).Left, StringGrid1.CellRect(X, Y).Top, cb.Width, cb.Height);
  end;

procedure TForm1.StringGrid1DblClick(Sender: TObject);
begin
    StringGrid1.Cells[0,StringGrid1.row] := iif(StringGrid1.Cells[0,StringGrid1.row]='True','False','True');
end;
 
 
 
procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
Var
  cVal:String;
  nARow,nProcesado : integer;
begin
  cVal := StringGrid1.cells[ACol,ARow];
  if (Arow>0) and (Acol>1) and (aCol<4) then
  begin
     StringGrid1.Canvas.FillRect(Rect);
     if SameText(StringGrid1.Cells[0, ARow],'True') then
       DrawFrameControl(StringGrid1.Canvas.Handle, Rect, DFC_BUTTON, DFCS_BUTTONCHECK or DFCS_CHECKED)
     else
       DrawFrameControl(StringGrid1.Canvas.Handle, Rect, DFC_BUTTON, DFCS_BUTTONCHECK)
  end;
 
end;