There's a few points that never really came up here. First of all, having mandatory birth control is as much of a trample on human rights as forcing somebody to quarter troops. The point is we are to maintain human dignity. Even if we KNOW we can help somebody, it is not our place to do so unless that person wants the help. A policy of mandatory birth control at puberty is a disgusting oversight of human rights.
Secondly, abortions, no matter what your view on the morality of them, will occur anyway. Abortions are like alcohol--anybody can make it happen in their basement. Forcing persons who want abortions into back-alley situations would be about as successful as prohibition, and in outlawing abortions you are putting two lives at risk instead of one (if you already believe the unborn is considered a life).
And people assume that when a person gets an abortion, they had weighed the possible ramifications of sex before they had it. A large portion of abortions are received by kids who were too young to be legally having sex with each other, and certainly not old enough to be considered responsibly weighing such options. Many are likely to not understand birth control doesn't always work. In fact, many adults don't understand birth control does not always work.
In addition, while rare, sex isn't the only way to get pregnant. Engaging in sexual behaviors, but not actually engaging in sex, is what a lot of persons suggest for couples who want to remain safe but romantically active. However, in some cases sperm can penetrate from landing around the vagina, without the penis being inserted at all.
Finally, a personal view on something as controversial as abortion comes out in every argument. But until at least 90% of a population can agree on a topic about ability to choose, should personal views of even 60-70% of a population affect the rights of an entire population? Remember, back in the heyday of slavery, it was considered not only moral but a favor to the otherwise doomed negro race. Now we know such a concept was ridiculous, even though it was held by a majority of the American population.
Which just goes to show, the majority is not always right. Isn't it safer to allow a choice on any subject that is not seen as immoral by all of the persons it affects, or at least a hugely significant majority?