Final answer:
A lethargic condition caused by a recessive lethal allele would persist in all offspring of carrier mothers through multiple generations.
Step-by-step explanation:
In cases where a lethargic condition is caused by a recessive lethal allele, the condition would persist in all offspring of carrier mothers through more than one generation. An example of this type of inheritance pattern is Tay-Sachs disease, a fatal disorder of the nervous system. If both parents are carriers of the faulty allele, their offspring will develop the disease and usually die in childhood.