Normal, yes, but don't go thinking you have to accept it. Your saddle could be positioned badly for you, or even the wrong shape. Your weight should be taken by your sit bones and numbness can happen when you're taking the weight on the perineum. Are you sitting on the nose of the saddle rather than further back? It MIGHT be as simple as moving the saddle forward a cm or 2.
There's some conjecture as to whether sitting on the perineum can cause lasting damage but, either way, numbness 'down there' is certainly not a pleasant feeling. Or maybe it is, whatever floats your boat!