I am not a doctor or a medical professional. I only know what I've read. But I know misinformation when I see it, and one glaring example of this is the oft-repeated mantra of the opponents of abortion rights: "life begins at conception". I'm not going to argue the usual opposite, which is that "life begins at birth".
I'm going to argue that life doesn't "begin" at all.
In humans and other mammals, a child is the product of conception and fertilization. Genetic material from a male and a female combine in a single cell, which gestates in the female. Early in the process of cell division, where the single cell replicates and specializes its descendants, it is also possible that twins, triplets, etc. will develop.
At what point did "life" begin here? If we're talking about biological life, it never stopped, nor did it start. It simply continued, with two biological entities (the sperm and the egg) contributing genetic information to the next generation of cells. Even after the blastocyst attaches itself to the uterine wall and begins to grow, it is essentially a part of the mother's body. It is genetically differentiated, but still as dependent on her health and nutrition for life as (say) her liver would be.
If we mean "life" as "human life" or an identity, it still hasn't begun. There is potential for what we think of as a human being to develop, but there is also the chance that it simply won't. In the early stages of development, there is no nervous system, much less a brain to house any sort of consciousness or cognition. There is certainly a developing embryo, which you can think of as a person, but that is your anticipation of the future - not the current state of affairs. Further, you may decide at the very moment of conception that you have a child, and may dream of naming it and holding it and cradling it, only to discover that you in fact develop twins.
Finally the blessed event occurs. A child is born. The lucky couple are treated to the first sight of their newborn at the hospital. Perhaps they've chosen a name. They know its gender by now, thanks to ultrasound.
Does the child now have a human identity? It is a living human being. It has birth records. It's integrated into society. But what about the child's mind? If you think that children are born with fully-developed egos and need only learn about the world they live in, perhaps you will be tempted to think that "life" - human self-identification in this case - has begun at birth. However, this does not appear to be the case.
Identity is something that accretes as an infant develops. Slowly, gradually, signs become visible that a child recognizes itself as an actor in the world. It's not an instantaneous process, and much of it is helped along by biological instinct (such as breastfeeding). And at last, at some point after the child is born, it finally recognizes itself as a human being.
This is not a defense of late-term abortion, nor is it intended as a defense of abortion at all. I don't believe in abortion, but I also don't believe that it should be made illegal. The debate over abortion has almost entirely been a debate involving interpretation of emotionally-charged ideas like "life" and "murder". To me, the key to finding a sensible national policy on abortion lies in clarifying just what it is we're talking about. We can't be truly successful in what we advocate unless we're honest about what it is we're really advocating.