Is goiter contagious?

No: You cannot "catch" a goiter from others. But there are parts of the world with iodine deficiency, so that many residents will develop goiters. Within families, there may be a predisposition to auto-immunity, so that the immune system makes antibodies that target thyroid proteins, and can cause multiple family members to develop a goiter.

No: Although the cause of goiter (enlarged thyroid) is usually not known, there is no evidence to suggest that it is contagious.