How can lesbians have biological children from both sides?

Answer 1

This is worded very oddly, but from what I think you're saying, is that "Can two women have a biological child that comes from both of their genes/DNA?" The answer is no. An egg cannot fertilize another. And even if two were to, or there was gene manipulation, it would still be impossible. It has to do with the Y chromosome. Without it, the cell could not divide, and it would just remain as one gertilized cell until it dies. Even if then that happened, it would be a 1000% chance female. Also, there are two chromosomes in a pair, 23 pairs (the last one being XX/XY, which determines gender). In each pair, one is carried by the female only, and the other by the male only. The only possible result would be a major birth defect, or even lack of life. It wouldn't represent anything close to human, and it almost definitly lack the tissue to survive.

In short, no-for SO MANY REASONS