**1.2. "Why did it happen? Will it happen again? What can be done?"**

These questions are perhaps among the most frequent during the counseling session and we will try to answer them briefly below. The probability reoccurrence is called "recurrence risk." Recurrence risk assessment and counseling is based on a combination of theoretic risk assessment and empiric data. Families and patients should be informed on the assumptions involved and the limitations of such estimates.

This chapter is focused on genetic counseling in congenital anomalies, caused by chromosomal, monogenic, or plurifactorial anomalies, as well as on preimplantation genetic diagnosis.
