Life insurance medical exam

I saw on TV one day an ad selling life insurance. Now that’s nothing unusual about it except the ad claims you don’t require a life insurance medical exam to apply! Now that can’t be right, can it? I mean how can you insure someone without knowledge of his health? It’s just not responsible on the part of the insurer because the insured could be riddled with all kind of health problems which the insurer will have to pay which will eventually be paid for by other members of the insurance company! Now that’s just wrong.