Spermatidogenesis is the creation of spermatids from secondary spermatocytes during spermatogenesis.
Secondary spermatocytes produced earlier rapidly enter meiosis II and divide to produce haploid spermatids.
The brevity of this stage means that secondary spermatocytes are rarely seen in histological preparations.
In 2016 scientists at Nanjing Medical University claimed they had produced cells resembling mouse spermatids artificially from stem cells. They injected these spermatids into mouse eggs and produced pups.