The purpose of genetic counseling is to enable individuals and families to make important decisions about marriage,reproduction,and health management based on the facts of the genetic situation for which a risk is perceived.

for which a risk is perceived 是定语从句，which 指代 the genetic situation （遗传状况）。直译是：风险被感知到的遗传状况，“认为存在风险的遗传情况”。