Are conjoined twins hereditary?
A. As far as I know, there is no hereditary basis for conjoined twins, so please do not let this concern spoil your plans. Conjoined twins happen about once in every 50,000 births. We do not know the cause, but some experts suspect that there may be links with maternal poverty and/or malnutrition. The defect that causes conjoined twins happens very early in pregnancy – about two weeks after conception. Nowadays, in the UK at least, conjoined twins are diagnosed relatively early in pregnancy, thanks to ultrasound scans, and appropriate plans can be made for delivery and aftercare.
