Comment by cjtrowbridge | Hacker News Reader

Comment by cjtrowbridge | Hacker News Reader

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The article title is a factually incorrect representation of the study being discussed. If you read the article and the study, you'll see the study was about changing chromosomes in a cell line, not about changing the sex of a person.

Everything about primary and secondary sex characteristics would not be affected by changing someone's chromosomes. Homologous sex structures diverge before birth based primarily on dht metabolism. Even then, chromosome expression doesn't always determine how dht will metabolize, meaning whatever chromosomes a person has can still lead to someone having any kind of primary and secondary sex characteristics. The six most common sex chromosome patterns in humans are XX, XY, XXY, XYY, X, and XXXY (in that order).

Sex and gender are both far more complex than merely chromosome expression, and chromosome expression is anything but a binary. This study has nothing to do with being male or female.

From the article:

> “This is a very well-designed study that validates the notion that sex differences start early in development—and that they depend on the sex chromosomes because that’s the only thing that can account for those differences,” says Nora Engel, a professor of cancer and cell biology at Temple University, who was not involved in this work.

Is this your area of expertise?

It is. And that quote is correct.

There's two problems here. One is that XX/XY is not even a majority of the common human chromosome karyotypes, and changing karyotypes does not change someone's sex characteristics; those are determined at one specific moment during gestation, which may or may not be affected by changing the chromosomes beforehand, but certainly would not be affected by changing their chromosomes after that moment. Primary and secondary sex characteristics are determined by androgen metabolism, not by chromosome karyotypes.

Secondly most of the human karyotypes are not assigned a sex until some time after birth, and XY is often assigned female at birth because the divergence of homologous structures depends on androgen metabolism, not chromosome karyotype. Sex and gender don't exist for cell lines in the same way they do for people.

TL/DR; This is an article about a study that found they could change a cell line's karyotype, not a person's sex characteristics which are determined not by chromosome karyotypes but by androgen metabolism during gestation. Whoever wrote the headline didn't understand the topic.

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