The medical textbook "Gray's Anatomy: The Anatomical Basis of Medicine and Surgery" documents that "the heart tubes fuse into a common loop" and "contractile activity commences" at 21 to 27 days after fertilization. Likewise, the textbook "Biology: Investigating Life on Earth" states that the human "embryo has its own circulatory system, complete with a heart that started beating only 24 days after conception...." Also, the Merck Manual explains, "The heart and major blood vessels begin to develop earlier - by about day 16. The heart begins to pump fluid through blood vessels by day 20, and the first red blood cells appear the next day." Some media outlets have tried to deny this reality by cherry-picking the claims of a few "experts" with a history of abortion activism. However, facts from science publications like the ones above prove just the opposite.