The obvious answer is you can't. Well at least, politically. It would take a huge societal change for the abortion debate to be settled. It's not like issues where everybody has the same goal, but takes different paths to achieve it (e.g. Reducing poverty through either liberal (school choice, credits, vouchers, philanthropy) or leftist solutions (unions, government spending)).
No, this is an issue that won't be settled via legislation, because both sides want different things entirely.
What about a hypothetical new technology?
And do you think there are any other issues out there, like abortion, where both sides want entirely different things?