were at any more at risk for Tay–Sachs disease than the general population, when the risk of Tay–Sachs among the general population was between 1 in 200 and 1 in 300, and when the Tay–Sachs test was "generally useless" for the vast majority of patients. The plaintiffs may also prove the negligence element by showing that the doctor failed to properly disclose the availability of genetic or prenatal screening procedures. As in other failure to disclose cases, the plaintiff will need to show that doctor owed a duty to make the disclosures at issue. Harm The plaintiffs in a wrongful birth case may claim that their harms consist in having a child with an undesired abnormality, or in having been denied the opportunity to make a fully informed choice as to whether to conceive or to abort the fetus. Cause In the past, plaintiffs have had to prove cause by showing that if the defendant had not been negligent, the child would have been normal. Under this standard, the defendant may argue that even if she or he failed to diagnose an existing fetus with a genetic or developmental abnormality, she or he did not cause the parents or fetus to have mutated genes or the fetus to develop the abnormality. Once the fetus is determined to have an abnormality, the doctor may not be able to treat the fetus, making the abnormality inevitable. If the doctor fails to diagnose the plaintiff's risk of transmitting a genetic disease, or fails to inform the plaintiff of that risk, then it is the combination of the parents' genetic mutations and choice to have a child that most directly results in the conception of an abnormal child. Because of difficulties in proving cause under this standard some courts disallowed wrongful birth suits. More recently, plaintiffs have been able to prove the causation element by showing that the defendant's negligence deprived them of the opportunity to fully consider the choice whether or not to conceive or abort their fetus. However, the plaintiffs must still prove that had the doctor acted properly they would have declined to conceive or would have aborted their abnormal fetus. This standard for causation has allowed plaintiffs to more easily prove the causation element. Still, the plaintiffs' claim that they would not have had an abnormal child is in some ways speculative. The decision whether or not to conceive given