Why we need a mother and father to give birth a child

i have this question long long time ago.

why we need a mother(female) and father(male) to create a child. isn't it 多鬼餘 particular when we can't find an opposite sex that is willing to reproduce with you. it totally reduce the possibility of extension of one species.

from a genetic perspective, yes, we can create a new born by using one gene, either father or mother. since the father/mother using only his/her gene to create a new born, theoretically, we can only call this activity an imitation or copy. it is because there is no change in DNA, just like we copy a piece of writing, the content of both are the same. we can also said that there is no improvement from this activity.

seeking for improvement, we have to introduce new thing in, so adopting another DNA is important. as we know that, after sexual intercourse, the father and mother genes with "fight" for each other, and the strongest win, the new born is a result or product of these "fighting", so the born must become better than or not worse than its father and mother.

beside improvement perspective. we still have to ask a question if we use only 1 host gene to create a new born "imitation of one self". imitation is an action to create yourself to take over yourself due to because the old one will old and die. if we neglect the social factor, the new one and old one are identical. if one day we can transfer our mental from one body to another body. does it mean that we can extend one life forever? body by body.

mother nature chooses improvement, so it structure the law by using competition in order to generate new life. this is what she chooses.