Why do humans “default” to female in fetal development?

Question

Is there any inherent reason why the body becomes female unless “told” by the Y-chromosome to be male as opposed to the other way around?

In: Biology

Answer 1

The y chromosome in the xx, xy chromosome pairs responsible for sexual characteristics is a mutation. The early stages of fetal devlopment are pretty much the same with major organs like eyes, heart, lungs, and brain. The devlopment of testies from ovaries is a modification that happens later in devlopment, without a lack of distinguishing features, and those differences being prevalent in the male, the ‘default’ is female. The female fetuses also have modifications to their sexual organs as they devlop but the are less obvious.