On January 22, 1973, the U.S. Supreme Court in two separate decisions (Roe v. Wade and Doe v. Bolton) ruled that any state abortion law in the future would have to meet the following guidelines:

First Trimester: During the first three months of pregnancy, the state must leave the abortion decision entirely to a woman and her physician.

Second Trimester: After the 1st trimester and until viability, the state may only enact laws which regulate abortions in ways “reasonably related to material health.” This simply means that a state may determine who is qualifited to perform the abortion and where it may take place. The state may not, however, enact laws to safeguard the lives of the unborn.

After Viability: (Now 20 weeks but then estimated by the Court at sixth or seventh month of pregnancy.) The law may forbid her to have an abortion that is not determined to be necessary to preserve her “life or health”. The Court went on to define the word “health” in such broad terms – i.e. social well-being – as to make it virtually impossible for a state to protect the unborn child at any time during the nine months. 

Thus, 7 Justices of the Supreme Court (9 total), disregarding prior legal tradition, overwhelming biological evidence and the ethical traditions of a majority of the American people, struck down the abortion laws of all 50 states (even the most permissive at the time) and made abortion on demand, at virtually every state of pregnancy, the law of the land.

On January 22, 1973, the Court gave the United States the dubious distinction of having the most permissive abortion law of any nation in the western world. Both Roe and Doe were decided by 7-2 votes.