A short answer to "who decides"?
Technology increases the control which experts and the medical professions exercise over conception, pregnancy, and childbirth. However, it is women and women alone who should make the ultimate decisions regarding their own childbearing.
D001294:Attitude to Health; D005260:Female; D006801:Humans; D010332:Paternal Behavior; D010358:Patient Participation; D011247:Pregnancy; D012098:Reproduction; D014933:Women's Rights