It's not advisable to breed a 6-month-old American Shorthair, as they are still considered kittens and are not yet physically mature. Breeding too early can negatively impact their health. It's best to wait until they are around one and a half years old, which is typically around their second heat cycle, before considering breeding.
A 6-month-old American Shorthair is too young for breeding. While American Shorthairs generally reach sexual maturity around seven months, their bodies are still developing. Specifically, the pelvic bones might not be fully developed to allow for a smooth delivery. Although mating at the onset of sexual maturity could potentially increase the chances of conception, it also significantly increases the risk of complications, such as difficult births (dystocia). If a kitten breeds and successfully conceives at this stage, the kitten's own growth and development can be hampered, leading to a smaller stature, weakened health, reduced lifespan, and can also result in the birth of weak, underdeveloped kittens with a lower survival rate. Therefore, it's strongly recommended against breeding a 6-month-old American Shorthair. Instead, wait until the cat is around one and a half years old—during its second heat cycle—when their bodies have reached full maturity and are more suitable for breeding. This is the ideal time to breed, ensuring both the mother's health and the well-being of any offspring.