An explanation is needed for why some men and women show positive in hCG screening tests when they are not pregnant, do not have cancer and are otherwise asymptomatic. In this study, a total of 10 families comprising 30 persons with a history of positive hCG tests were investigated. Total hCG was measured in serum and urine samples using the Siemens Immulite hCG test. Total hCG, C-terminal peptide determinant, and hCGβ were measured in 96 well plate assays. Twenty-four of 30 family members produced only hCGβ, and hCG or hCGβ missing the β-subunit C-terminal peptide, two rarely detected hCG degradation products as the only source of hCG immunoreactivity. In every one of the 10 families, hCG related molecules were detected first in one member and then later detected in other family members. In 8 of 10 families, all members produced comparable hCG concentration (Cases 1-8). All of the 10 original family members investigated were otherwise asymptomatic, and tested negative in ordered head and pelvis MRI scans and CT chest cancer tests. None had been administered hCG for dietary, anabolic or fertility reasons. Therefore Familial hCG Syndrome, a genetic defect, was indicated in each of the 10 families. In these cases of Familial hCG Syndrome only biologically inactive variants of hCG were detected. It is inferred that in Familial hCG Syndrome, hCG gene expression does not interfere with fertility.