It is God the Holy Spirit who gives physical (as well as spiritual) life.  Psalm 104:30 says:  ‘When You send forth Your Spirit, they are created, and You renew the face of the ground.’  And Job 34:14-15 says:  ‘If He should set His heart to it and gather to Himself His Spirit and His breath, all flesh would perish together; and man would return to dust.’

Taking into account also the fact that it is God who knits us together in the womb, and knows us even before we were conceived, we should be very careful not to interfere with the crowning glory of His creation:  human beings.