Gladly! I found an article from a scientific journal that does not support your claim that consciousness begins 12 weeks after conception.
According to the source below, "the thalamo-cortical complex that provides consciousness with its highly elaborate content, begins to be in place between the 24th and 28th week of gestation." In layman's terms, the things yin your brain that makes consciousness doesn't even begin to develop until the 24th to 28th week after conception. And that doesn't mean the baby is conscious then, just that there is no way that consciousness can begin before that.
Also, the article points out (this is based off of many examples in the article, which you can read yourself) that in the uterine environment, "the fetus is asleep while its brain matures." Essentially, throughout the months of pregnancy, the baby's consciousness is not active.
So when does consciousness begin? Well, believe it or not, birth. "The dramatic events attending delivery by natural (vaginal) means cause the brain to abruptly wake up." This state of 'sleep' in which the brain's consciousness was not active and present is ended by the act of being delivered.
The article closes with the point that after the baby is born, "It draws its first breath, wakes up and begins to experience life."
So based on all this evidence, your claim is false.
I urge you to read this article. Since your view on abortion is based on science, you should be aware of all the science involved with abortion. Perhaps you will be able to change your view on abortion again, since you changed it the first time due to science.
http://www.scientificamerican.com/article/when-does-consciousness-arise/?page=1