Both statements are correct in the context of mitochondrial diseases. Mitochondrial inheritance is maternal, meaning a child inherits mitochondria—and thus any mitochondrial diseases—entirely from the mother since the sperm contributes little to the mitochondrial DNA of the offspring. Mitochondrial replacement therapy (MRT) can prevent these diseases by replacing defective mitochondria in a mother's egg with healthy ones from a donor, thereby allowing for the possibility of healthy offspring either before fertilization (pre-fertilization MRT) or through techniques post-fertilization (post-fertilization MRT), effectively breaking the transmission of these inherited diseases.