In Federal law, the concept of legal personhood is formalized by statute (1
USC §8) to include "every infant member of the species homo sapiens who is born alive at any stage of development." That statute also states that "Nothing in this section shall be construed to affirm, deny, expand, or contract any legal status or legal right applicable to any member of the species homo sapiens at any point prior to being 'born alive' as defined in this section."
According to the National Conference of State Legislatures,
[24] many US States have their own definition of personhood which expands upon the federal definition of personhood, and
Webster v. Reproductive Health Services declined to overturn the state of Missouri's law stating that
"The life of each human being begins at conception . . . Effective January 1, 1988, the laws of this state shall be interpreted and construed to acknowledge on behalf of the unborn child at every stage of development, all the rights, privileges, and immunities available to other persons, citizens, and residents of this state, unborn children have protectable interests in life, health, and well-being."