Ever since 1973, pro-lifers have maintained that viability depended on our ability to care for a baby, not on the baby's age. At that point the Supreme Court wanted to place viability at the end of the "second trimester" Now the New England Journal of Medicine has published a study which essentially finds that the chance of healthy survival for babies born at 22 weeks depends on the attitude and ability of the hospital. You need to subscribe to read the study but the NY Times has a good article about it.
Just another place where the Supreme Court did not think things through before sentencing tens of millions of babies to death.
Of course, viability could apply to people who are disabled, elderly or ill...
Keep up the good work!