女生外相。。。
哈哈哈
--------从DNA遗传来看,只有儿子才能将Y0遗传下去
X0Y0+X1X2---->儿子：Y0X1 or Y0X2
------------->Y0X1+X3X4------------->孙子1：Y0X3 or Y0X4
------------->Y0X2+X3X4------------->孙子2：Y0X3 or Y0X4
------------->Y0X1+X3X4------------->孙女1：X1X3 or X1X4 (100%无0类DNA)
------------->Y0X2+X3X4------------->孙女2：X2X3 or X2X4 (100%无0类DNA)
X0Y0+X1X2---->女儿：X0X1 or X0X2
------------->X0X1+Y3X5------------->外孙子1：Y3X0 or Y3X1 (50%无0类DNA)
------------->X0X2+Y3X5------------->外孙子2：Y3X0 or Y3X2 (50%无0类DNA)
------------->X0X1+Y3X5------------->外孙女1：X5X0 or X5X1 (50%无0类DNA)
------------->X0X2+Y3X5------------->外孙女2：X5X0 or X5X2 (50%无0类DNA)
