A new electrochemical biosensor based on the sequence of chromosome Y (SRY) has been introduced to determine the gender of the fetus. At frst, the DNA probe was designed based on the SRY gene sequence on chromosome Y. Then, a suitable functional group was added to the DNA probe, and it has been immobilized on the surface of the electrode modifed with a nanocomposite containing Cu(OH)2 @N–C n-boxes. This substrate causes more DNA probes to connect to the electrode surface by increasing the efective surface area. The presence of the SRY sequence in the DNA sample extracted from blood was detected by the electrochemical signal of the bio-sensor. After optimizing the parameters, the fabricated genosensor showed linear responses in the two concentration ranges containing 0.5 fM to 50 pM and 50 pM to 500 nM. The limit of detection (LOD) for the proposed method was 0.16 fM. The proposed genosensor has been successfully used to determine the gender of the fetus using cell-free fetal DNA (cfDNA) in the blood plasma of several pregnant mothers. This method has advantages such as being simple, portable, accurate, and non-invasive for early determination of the gender of the fetus and early diagnosis of X-linked genetic disorders
