The bill is the result of five years of campaigning by mothers like Heidi Kauffman, who told The Philadelphia Inquirer, "People think it's only a piece of paper, but it was kind of like saying he never happened," adding, "I was pretty mad at the world, but I was appalled that I could hold that perfect beautiful baby, and the state would say he never existed." A Facebook page for the campaign includes photographs of the stillbirths.
In the debate over this bill, as in other states, some pro-choice legislators raised concerns about the implications of such a bill. That's because the further reaches of the anti-choice movement have tried to introduce fetal personhood legislation in states like Colorado in order to grant embryos and fetuses the same rights as the born, and the worry has been that vague language in a stillbirth birth certificate bill could be a slippery slope to the same.
A stillbirth is the death of a fetus anytime after the twentieth week of pregnancy; in Pennsylvania, traditionally an abortion-rights battleground (it was the site for Planned Parenthood v. Casey, which established the "undue burden" standard for state limits to abortion rights), abortion is legal up to 24 weeks unless there is a risk to the health of the mother.
According to a national website advocating for these Missing Angels laws (which apparently hasn't been updated in a few years, and which quotes Roland Barthes on the homepage), the first such law went into effect in Arizona in 2001. Of the groups that expressed wariness, the advocates said,
We believe they don't wholly understand the issue. In a statement by Kim Gandy, President of the National Organization for Women, on CNN's American Morning in January of 2007, Gandy's position on this bill was that they would not have a problem with it as long as it met two criteria: 1) the document would exclude abortions and 2) that it would be optional. We have taken special care to emphasize that elected terminations are not included and that the document would be optional.
In Pennsylvania, the law is optional; parents have to apply to get the certificate of birth resulting in stillbirth.