This is on YouTube. It’s his voice. I cannot vouch for the authenticity of it, but I trust the friend who sent it to me.
In the audio, Obama raises a new argument against the Born Alive Infant Protection Act that he has not raised in public during the present discussion. The description of the YouTube clip sums it up:
In this audio Obama coldly claims two doctors helping a baby born alive after a botched abortion would be a burden for the aborting mother when he is arguing against the Born Alive Infant Protection Act at the Illinois state legislature April 2002