- Over-population
- Infertility
- Evolution and breeding
- Frank Herbert: Dune series (1965) (Bene Gesserit sisterhood has intense breeding program lasting thousands of years)
- Lois McMaster Bujold's Barrayaran series (The Cetagandans are involved in a long-term human breeding project)
- Greg Bear: Darwin's Radio (1999) (ultra-rapid evolution of homo sapiens whilst still in utero due to a retrovirus)
- technology
- Hybrids