Man booked in death of fetus

How can this be? Haven't we been told by the left that the fetus is not a human being? The fetus involved was only 18 weeks old (link) That's 4 & 1/2 months. Again we are faced with a hypocrisy. The mother involved could have chosen to kill her fetus without repercussions, but since a father did it, he is charged with murder. We now have a system in which the legal status of a fetus ( human being, or unwanted clump of cells) is entirely dependent on the personal preferences of the mother. If this fetus was a human, and thus it's death a homicide, then all fetus are human and should be granted the same protection, regardless of whether their mother is killing them, or someone else is.