\text{1. In vitro fertilization (IVF):} This is a high complexity technique where eggs are fertilized by sperm outside the body.
\text{2. Intracytoplasmic sperm injection (ICSI):} Also high complexity, where a single sperm is injected directly into an egg.
\text{3. Cryopreservation of gametes and embryos:} High complexity, involving the freezing of sperm, eggs, or embryos for later use.
\text{4. Preimplantation genetic screening (PGS) / Preimplantation genetic diagnosis (PGD):} High complexity techniques used for detecting genetic defects in embryos before implantation.
\text{5. Gamete intrafallopian transfer (GIFT) and zygote intrafallopian transfer (ZIFT):} These can be considered lower complexity compared to IVF and ICSI, involving the placement of sperm and eggs (GIFT) or a fertilized egg (ZIFT) into the fallopian tubes.
**Answer: A detailed break-down and classification of assisted reproductive techniques**