Minato CAN'T be Tsunade's Kid
This is a fan theory I've seen thrown around, even by famed YouTuber NCHammer23. NCHammer is very good at his job, but this theory? It's bad.
The theory is that Tsunade is Minato Namikaze's mother. Why? Because they're both blonde? That's rather shallow. Because the ages line up (even if it results in a teen pregnancy)?
Yeah...uh...about that...
Those of you that have seen my Naruto essays know that I took the timeline created by Seelentau and modified it, both with my own fan ideas and things that I felt were weird narratively (even if the math was accurate). Generally, I do not mess with established birth years. The few times I have, it was to iron out inconsistent data...and one slight arbitrary shift with Shisui.
I have not, however, ever touched Minato and Tsunade's birth data. Minato was born on January 25 about 24 years before Naruto was born. Tsunade, who was 51 in Part 1 (Naruto's 13th year of life), was born on August 2, 38 years before Naruto was born.
Of course, those numbers are negative, and positive numbers are better. On my timeline, I shifted the marker from Naruto's birth to the foundation of Konoha. As a consequence, all those negative numbers had fifty added to them.
This means the new birthdates are:
Tsunade: 08/02/12
Minato: 01/25/26
Right off the bat, you will notice that Minato was born in Tsunade's 14th year of life, which is...very uncomfortable. But it's worse. Count the months. If Tsunade had a baby in January of 26, then she would have been 13, the very edge of a teenager. And it gets worse still...
Let's presume a nine month pregnancy. If so, then Tsunade would have had to have gotten pregnant...at twelve. We wouldn't be looking at teen pregnancy, we'd be looking at pre-teen pregnancy. And don't think you can go for premature birth, either.
In order to avoid the extra-grossness of a pre-teen pregnancy, Minato would have to have been born in less than six months. I am not a medical professional, so I can't say exactly how dangerous that is, but I can say with certainty that it is dangerous.
The earlier a kid is born, the more danger there is, and being born very premature comes with developmental issues and potentially lasting health issues.
A number of preemies (that's what nurses call premature children) end up with some degree of cerebral palsy, a disorder where damage to the brain causes neurological and muscular problems, learning disabilities, growth and development issues, and so on. And that's only one result of premature birth. There are other things that can go wrong. Some children just die.
Minato, as far as we can see, doesn't seem to have any medical issues, and believe me, if he was born extremely early (less than six months), he would have something. Such things would have impacted his ability to be a ninja anyway. Therefore, it seems very unlikely he was a very early preemie.
This theory doesn't work. The math doesn't work. It adds up to something really dark and severely messed up that no one in their right mind would use for fiction.
