Approximately how long does one full cycle of spermatogenesis, from spermatogonia to formed sperm, take?

1. Spermatogenesis is a continuous process that begins at puberty and proceeds throughout adult life. 2. A single cycle progresses through several defined stages of division. 3. One complete cycle takes approximately 64 days. 4. A new cycle starts roughly every 16 days, which is the interval between cycle starts, not the length of one full cycle, so that value is ruled out. 5. 16 days and 7 days are both different figures a reader might guess from memory, but neither matches the specific figure given here. 6. So 64 days is correct. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 27 "The Reproductive System", p.1284 §Spermatogenesis_