That's not really true.
Sicence can tell you exactly when personhood happens. So long as you have a definition of personhood.
Really, based on that abortion can happen between never, and up to the age of two.
Really abortion is a much more interesting issue then the banal arguements that keep reappearing... conected to a lot of interesting issues.
As it is, most people on both sides have some huge contradictions in their stances because they don't put proper thought into it.
As for planned parenthood. That seems more about cutting back on government services that don't pay for needs.
What I'm saying is that there is no scientific definition of personhood.