Increasing prenatal diagnosis of chimeras with the use of noninvasive prenatal screening: Report of two cases

Bulleted Statements: What's already known about this topic? The incidence of discordant fetal sex was estimated to be 1 in 1500–2000. Comprehensive evaluation is required to investigate the underlying cause. What does this study add? Chimera is one of the possible causes of genotype–phenotype sex discordance. It could be detected prenatally with the combination of noninvasive prenatal screening and ultrasound. Genetic counseling to prospective parents on chimera can be complex where early support and information from experienced professionals are important.