This chapter identifies the risks to which couples are exposed by the unjustified use of intracytoplasmic sperm injection (ICSI). While various studies have reported higher fertilization rates with ICSI than with in vitro fertilization (IVF), this is unproven, and clearly untrue in centers with good IVF systems. Many centers have published a prevalence of total IVF fertilization failure (TIFF) of 5-10%, or even higher, yet others report values of 2%. This discrepancy, and the finding of high rates of TIFF, is the result of two main issues: poor andrological evaluation of the male partners and poor sperm handling/preparation/capacitation systems that result in impaired sperm function in vitro. A number of centers employ IVF/ICSI splits, where the available oocytes are assigned to two groups, one for conventional insemination and the other for ICSI. However, with splits it is not uncommon for the better looking cumulus-corona-oocyte complexes to be assigned to ICSI.