Viability is the point at which a fetus can survive outside the womb. There are two types of viability: natural viability and medically assisted viability. Natural viability is the point at which a fetus can survive outside the womb without medical intervention—about 35 weeks of gestation. Medically assisted viability is the point at which a fetus can survive outside the womb with medical assistance—about 24 weeks of gestation. Many people like viability as a marker of fetal personhood because from their perspective, all living people can survive outside of a uterus. One struggle we have with using viability as a marker of personhood is that we can only see viability as a statistic of how many babies survive an early birth. For example, only 40-70% of babies born at 24 weeks survive. Is it okay to have 24 weeks gestation be a threshold for personhood when 30-60% of fetuses are unable to survive outside of the uterus at that age? It's a hard call. Here are viability statistics from 21-34 weeks of gestation from the US Department of Health and Human Services

  • 21 weeks or less: 0%

  • 22 weeks: 0-10%

  • 23 weeks: 10-35%

  • 24 weeks: 40-70%

  • 25 weeks: 50-80%

  • 26 weeks: 80-90%

  • 27 weeks: more than 90%

  • 28 weeks: 92% or more

  • 29 weeks: 95% or more

  • 30 weeks: more than 95%

  • 31 weeks: more than 95%

  • 32 weeks: 98%

  • 33 week: 98%

  • 34 weeks: 98% or more

A second struggle we have with viability as a marker is that, as medical treatments have become more advanced, the timeline for medically assisted viability is moving earlier and earlier. This is problematic because technology-assisted viability is very expensive. An extreme preemie baby born at 24 weeks will have to spend at least two months in a NICU, which costs about one thousand to three thousand dollars per day. A third struggle with viability is that the earlier a baby is born, the higher the chance they have of developing disabilities or life-long health problems such as cognitive and neurological impairment, lung disease, blindness, or deafness.  See for more preemie health statistics. Because of these issues, viability is a very problematic marker of personhood.