Do people with Down Syndrome have a right to life?

A post I published in this blog in 2017 ended with this paragraph:

Why are human beings conceived with trisomy of chromosome 21 (Down syndrome) denied the right to life, to the point that, in many Western countries, in practice they are not allowed to be born?

In another post, published in 2015, during the first year of this blog's existence, I calculated the probability that the triple and quadruple screening tests, then in use to detect trisomy of chromosome 21 (the cause of Down syndrome), would produce false positives. The conclusion was this:

A global conspiracy?

Isaac Asimov

In 1976, at the peak of the pessimistic forecasts about the catastrophic rise in global population, foreseen by the first report of the Club of Rome (1972), Isaac Asimov published a science fiction short story (The winnowing), which suggested a (highly unethical) way to stop this catastrophic increase in population. This is the summary of the story:

In 2005, the unstoppable population growth causes famine in the third world countries. To contain it, the world authorities (the UN), controlled by the developed world, decide to apply a triage to the world population. To do this, a scientist (who does not want to do it, but is threatened with reprisals against his family) is ordered to develop a protein, poisonous for 70% of the population, but harmless for the remainder, depending on each individual DNA, so that its effects will be dramatic, but random. The protein will be introduced in the food sent to alleviate famines, so as to bring the world population down to more manageable levels. The project is not applied exactly as planned, because the biologist who must develop the protein gives it to eat to the world leaders without their knowing, so that 70% of them will die. As the protein has been adapted to the scientist’s DNA, by eating it he commits suicide, thus escaping the consequences of what he has done.