For centuries, the word "child" primarily referred to unborn babies. Then, during the liberal push to legalize abortion in the latter half of the 20th century, referring to an unborn child as a "child" suddenly became problematic. So liberal activists and academics began referring to unborn children using the medical terms "fetus" and "embryo" (which are themselves merely stages of development like "infant" or "adolescent"), or they made up new terms like "the products of conception" (a term which describes all sexually reproducing organisms on Earth). More recently, liberals have begun simply not mentioning unborn children at all, instead referring to "pregnancy" and a woman's decision to "continue a pregnancy" or "end it" - which is like referring to a child as a "childhood" and killing a child as "ending a childhood", and asserting that it is a parent's right to decide whether to "continue a childhood" or "end it".