Sure. Thank you for the question.
Originally, before the legislative changes in 2007, Canadians who were adopting internationally had to go through a two-step process to sponsor the child. First was for immigration to Canada. Then, once the child became a permanent resident, they applied for citizenship. That process was criticized because natural-born children of Canadians living abroad were citizens from birth, so adoptive parents asked for a more streamlined process to access citizenship. The law changed in December 2007 to minimize the difference between the natural-born children of Canadians living abroad and the adopted children of Canadians.
Further changes were made to the Citizenship Act in April 2009, again to be consistent and to minimize the difference between these two groups. When the first generation was limited to the first generation abroad, it approached the two groups the same way and equally applied the first-generation limit to both the natural-born children and the adopted children of Canadians.