So popping a pill to get rid of a headache should require the same level of thought as popping a pill to get rid of the possibility of pregnancy.
Even if you are pro-choice and you don't believe life begins until a child is born, you have to appreciate the weight of a decision to have unprotected sex as a minor and the consequences that come with that. Rape is a different story. I'm talking about consensual sex between minors without contraception. Should we be saying, "Just go for it, and you can pop a pill in the morning as if what you did has no consequences."
Not to mention the emotional impact sex has on a person, particularly a young person. It's not a purely physical act like eating and drinking. The more we teach kids, directly or indirectly, that they should always act on their sexual urges and give them the means to do so thoughtlessly, the more we tell them the lie that there won't be any physical, emotional, or psychological consequences.