I recently heard a radio clip where the speaker was advocating the adoption as a cure to the abortion issue. While I completely agree that Christians need to really show themselves as more loving and being willing to help out those caught in a hard place, I think the reasoning was very simplistic.
First, the children of such situations are often the most sought after in the adoption area. Many potential adoptive parents are lined up for an infant, making such a child relatively easy to place. In fact, many of these couples are almost begging for a child. The message of this may need to get out, but that isn't the sole problem.
If the child has known special needs, perhaps due to poor behavior (such as drinking or drugs during pregnancy) by the mother, the parents may be in for quite a ride as the attempt to raise a child with serious issues.
Finally, adopting older children, including any that are no longer infants, carries its own serious risks. I am probably very jaded by my own experience, but the myth of "happily ever after" if we just love enough is just that, a myth. Older children carry their own load of problems and taking on such a child (or sibling group as we did) can make for a much more challenging road than most adoptive parents are really ready for.
We went through many "parenting classes" prior to adopting, yet none of them prepared us for the serious challenges we faced. I now vaguely recall being told many "horror stories," but we were too young and naive to believe them. After all, we would be different! We would work through anything and stay committed no matter what! Right?
While the zeal is necessary, some healthy reality is as well, along with a really strong support group, including government and social authorities that believe parents, not trouble teens that are willing to say anything to be free from these interlopers who are attempting to parent them.
Providing such strong support networks is much more important than any massive attempt to place all the waiting children. Not providing that will ultimately harm children more, and the families that try to adopt them. Leaving a child in the foster care system has serious issues, but throwing them into a family that is not prepared is also foolhardy.
Make sure you have some serious stamina if you are going to start down this road. And if you are advocating adoption as a solution, make sure advocate support for parents taking this step to an equal or greater degree. Otherwise, you are setting everyone up for a mighty crash.