Mass biological testing and screening for inherited traits and tests of brain function and intelligence could raise constitutional issues of equal protection, search and seizure, and privacy. Biological developments in the areas of abortion, surrogate parenthood, the determination of paternity and maternity, and the testing of fetuses could trigger privacy and due process concerns. These and other incursions on individual autonomy and freedom by new biological discoveries threaten some of the basic presumptions of our political system. The U.S. Constitution's guarantees of equality and privacy must be preserved. The new biology will call for a renewed focus on such ethical questions as the meaning of personhood and the sanctity of human life. 170 footnotes.