Little is known about the impact of genetic counseling on parental uncertainty or perceived control regarding the prognosis of a child with a chromosomal disorder. By exploring the parents' concerns and needs surrounding the child's diagnosis, a genetic provider can help to facilitate effective coping. This study tested the association of measures of parental uncertainty and perceived control with the perceived helpfulness of the genetic counselor. A survey was distributed to 875 members of the Chromosome Deletion Outreach (CDO) support group. We hypothesized that parents' perceptions about the helpfulness of the genetic counselor would modify the relationship between perceived uncertainty, perceived control, and coping. Among the 363 respondents, there was a significant negative correlation of the perceived helpfulness of seeing a genetic counselor with the levels of uncertainty (rs = -0.20, P-value < 0.001). Lower perceived helpfulness of the genetic counselor, along with less perceived personal control, less benefit of a diagnosis, and lower parental age were significant predictors of the highest perceptions of uncertainty. The Transactional Model of Stress and Coping was used as a framework for interpreting the relationships between parental uncertainty, perceived control, and outcome variables. There was a significant positive correlation between parents' perceived personal control and their reports of helpfulness of the genetic counselor (rs = 0.20, P-value <0.0006). Genetic counseling can be enhanced for parents faced with rare disorders by using interventions focused on reducing feelings of uncertainty and enhancing feelings of control.