Dear student,
Extinction of a gender from a population of a particular species(in this case female) means one gamete is absent from the population. As we know that for reproduction to occur both male and female gametes are required to form a new zygote or a new individual of the same species. Thus, elimination of females from the population will eliminate the chances of reproduction and hence after some time the population will totally extinct as no new individuals will be generated in that population.
The case of mutation of a male individual and producing offspring is highly unpredictable and fictional. For this to occur, there has to be long span of evolution to take place and even after that it seems very unlikely to occur.
Regards.