it is incapable of producing offspring but some of its kind is born each day?

Mules.

Mules are a crossbreed between a male donkey (also known as a jack) and a female horse (also known as a mare). They are known for their strength, endurance, and surefootedness. Mules are a unique case because they are incapable of producing offspring themselves, but they are still born each day.

To understand how this is possible, we need to look at the concept of sterility. Mules are sterile, which means they cannot reproduce because their reproductive organs do not function effectively. This is due to the difference in the number of chromosomes between horses and donkeys. Horses have 64 chromosomes, while donkeys have 62. When a horse and a donkey mate, their offspring (a mule) ends up with 63 chromosomes, an uneven number.

The uneven number of chromosomes makes it exceedingly rare for mules to have fully functional reproductive organs. Consequently, mules are unable to produce viable eggs or sperm for reproduction. This genetic difference prevents mules from successfully passing on their genetic material to offspring.

However, even though mules cannot reproduce, they are still born each day. This happens because mules are created through the mating of horses and donkeys, resulting in new mule offspring being born regularly. So, while mules cannot produce offspring themselves, their existence continues through the ongoing breeding of horses and donkeys.