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Genetic counseling is a communication process that aims to achieve as complete an understanding by the counselee(s) as possible, thereby enabling nondirective rational decision making. Studies examining the efficacy of genetic counseling in various settings and using different modalities (e.g. telephone versus in‐person) and self‐efficacy of genetic counselors and students continue.^1038–1041 Anxiety, distress, uncertainty, guilt, decisional conflict, and a deficient knowledge of science, together with difficulty in understanding a balance of risks, influence the ultimate efficacy of genetic counseling. Parental decisions to have additional affected progeny should not be viewed as a failure of genetic counseling. Although the physician's goal is the prevention of genetic disease, the orientation of the prospective parents may be quite different. A fully informed couple, both of whom had achondroplasia, requested prenatal diagnosis with the expressed goal of aborting a normal unaffected fetus so as to be able to raise a child like themselves. Would this be construed as a failure in genetic counseling? Would continued pregnancy with an anencephalic fetus after genetic counseling be considered a failure of genetic counseling?

Clarke et al.¹⁰⁴² considered three prime facets that could possibly evaluate the efficacy of genetic counseling: (i) recall of risk figures and other relevant information by the counselee(s); (ii) the effect on reproductive planning; and (iii) actual reproductive behavior. Their conclusions, reflecting a Western consensus, were that there are too many subjective and variable factors involved in the recall of risk figures and other genetic counseling information to provide any adequate measure of efficacy. Further, assessing reproductive intentions may prejudge the service the counselee wishes as well as the fact that there are too many confounding factors that have an impact on reproductive planning. Moreover, how many years after counseling would be required to assess the impact on reproductive planning? They regarded evaluation of reproductive plans as “a poor proxy for reproductive behavior.” In dispensing with assessments of actual reproductive behavior in the face of counseling about such risks, they pointed to the complex set of social and other factors that confound the use of this item as an outcome measure. They did, however, recommend that efficacy be assessed against the background goals of genetic counseling aimed at evaluation of the understanding of the counselee(s) of their own particular risks and options. A questionnaire study from the Netherlands questioned 1,479 counselees about their experience of genetic counseling. Questionnaires were administered before and after counseling and for the third time after results were disclosed.¹⁰⁴³ They noted improvement in the level of empowerment, personal control, and anxiety after the whole process.

Evaluation of the efficacy of genetic counseling should not only include the degree of knowledge acquired (including the retention of the counselee(s) with regard to the indicated probabilities), the rationality of decision making (especially concerning further reproduction), but also the potential personal influences outlined in the Netherlands' study. Frequent contraceptive failures in high‐risk families highlight the need for very explicit counseling. A further measure of efficacy is the frequency and accuracy of a proband's communication of important risk information to close relatives. It appears that communication of test results may be selective, with male relatives and parents less likely to be informed.¹⁰⁴⁴

Important points made by Emery et al.¹⁰⁴⁵ in their prospective study of 200 counselors, included the demonstrated need for follow‐up after counseling, especially when it is suspected that the comprehension of the counselee(s) is not good. This seemed particularly important in chromosomal and X‐linked recessive disorders. They noted that the proportion deterred from having children increased with time and that more than one‐third of their patients opted for sterilization within 2 years of counseling.

A number of studies^1045–1048 document the failure of comprehension by the counselee(s). Such failures are increasingly likely with genome sequencing resulting in secondary findings and revelations of unknown significance.¹⁰⁴⁸ The reports do not reflect objective measures of the skill or adequacy of genetic counseling and the real value of a summary letter to the patient of the information provided after the counseling visit. Sorenson et al.¹⁰⁴⁹ prospectively studied 2,220 counselees who were seen by 205 professionals in 47 clinics located in 25 states and the District of Columbia. They gathered information not only on the counselees but also on the counselors and the clinics in which genetic counseling was provided. They, too, documented that 53 percent of counselees did not comprehend their risks later, while 40 percent of the counselees given a specific diagnosis did not appear to know it after their counseling. They thoroughly explored the multiple and complex issues that potentially contributed to the obvious educational failure that they (and others) have observed. In another study of parents with a Down syndrome child, Swerts¹⁰⁵⁰ noted that of those who had genetic counseling, 45 percent recalled recurrence risks accurately, 21 percent were incorrect, and 34 percent did not remember their risks.

In considering the effectiveness of genetic counseling, Sorenson et al.¹⁰⁴⁹ summarized the essence of their conclusion:

In many respects, an overall assessment of the effectiveness of counseling, at least the counseling we assessed in this study, is confronted with the problem of whether the glass is half full or half empty. That is, about half of the clients who could have learned their risk did but about half did not. And, over half of the clients who could have learned their diagnosis did but the remainder did not. In a similar vein, clients report that just over half of their genetic medical questions and concerns were discussed, but about half were not. The picture for socio‐medical concerns and questions was markedly worse, however. And, reproductively, just over half of those coming to counseling to obtain information to use in making their reproductive plans reported counseling influenced these plans, but about half did not. Any overall assessment must point to the fact that counseling has been effective for many clients, but ineffective for an almost equal number.

A critical analysis of the literature by Kessler¹⁰⁵¹ concluded that published studies on reproductive outcome after genetic counseling revealed no major impact of counseling. Moreover, decisions made before counseling largely determined reproduction after counseling.

A study of patients' expectations of genetic counseling revealed that the majority had their expectations fulfilled, especially with perceived personal control.¹⁰⁵² When patients' expectations for reassurance and advice were met, they were subsequently less concerned and had less anxiety when compared with such expectations that were not fulfilled, similar to the Netherlands report.¹⁰⁴³

The limited efficacy of genetic counseling revealed in the study by Sorenson et al.¹⁰⁴⁹ reflects the consequences of multiple factors, not the least of which were a poor lay understanding of science.¹⁰³⁶ Efficacy, of course, is not solely related to counselee satisfaction. Efforts to educate the public about the importance of genetics in their personal lives have been made by one of us in a series of books (one translated into nine languages) over 50 years.^{184, 331, 335, 337, 338, 1053} In addition to public education and its concomitant effect of educating physicians generally, formal specialist certification in the United States, Canada, the United Kingdom, and elsewhere, acceptance of clinical genetics as a specialty, and degree programs for genetic counselors certified by the National Board of Genetic Counselors, has undoubtedly improved the efficacy of genetic counseling. There remains, however, a pressing need to better educate practicing physicians about the “new genetics”^{184, 185, 199, 1054, 1055} in this, the golden era of human genetics.