Fargo has also written in final of the Q&A that "Nothing is set in stone" which means that what was once impossible as the writing goes can become possible
╮( ̄▽ ̄)╭
http://www.mangago.zone/read-manga/love_is_an_illusion/uu/love_is_an_illusion-chapter-43.5/3/
But still I do not want them to have a child. This dude said it himself. He never wanted a child for himself. And I think the beta could use it as well. Since he always cared for everyone else, having a child you again be taking care of them. Imo he should live out his life more and enjoy it together with his boyfriend. There are a lot of child free people out there, be it gay or straight. They can work on their relationship and their goals in life without a child to tie them together. Because again, if their relationship is stable to begin with, why would they need a child to tie it together?
Fargo just emphasized in their twitter that betas can't get pregnant in this one, so a pregnant Heesoo is not happening. They said that if Heesoo and Dojun would adopt, a dog is preferred and not a child.