但是染色體！！！
TransEthics™
#BlackTransLivesMatter @TransEthics 
I'm going to regret paying the co-pay for this test eventually because it was pretty pricey… but I had my karyotype done. Just got the results.
I –a trans woman– have XX chromosomes.
the GC crowd can g[REDACTED]k themselves
染色體的複雜程度遠遠超過 XX 和 XY，有很多種情況。被稱為 DSD（性別分化多元性），並非所有情況都會導致雙性人狀況，而且許多情況只在青春期開始時才會出現。
- 德拉夏佩爾症候群（46,XX 男性）發生在精子母體的 SRY 基因在精子發生過程中交叉到非 Y 染色體的精子中時。當卵子和精子融合時，就會產生一個帶有 SRY 基因的 XX 胚胎，從而產生一個具有兩條 X 染色體的表型男性兒童。
-
斯威爾症候群（英文）（46,XY 女性）會產生一個帶有 XY 染色體的表型女性兒童。這是由十幾種不同的基因狀況引起的，包括：
- XX 性腺發育不全（英文）與斯威爾症候群非常相似，只是它發生在 XX 兒童身上，導致卵巢無功能。
- 特納症候群（45,X）會產生一個表型女性的兒童，並伴有許多異常。它發生在 X 或 Y 染色體都沒有從精子交叉過來的時候。
- 克林費爾特症候群（47,XXY）會導致一個表型男性的兒童，但具有更多女性化的特徵。在極少數情況下，它也出現在女性指定的兒童身上（英文），導致女性化的睪丸而不是卵巢。
- 48,XXXY 克林費爾特症候群（英文）的結果與 47,XXY 克林費爾特症候群相似，但健康問題更嚴重。
- 49,XXXXY 克林費爾特症候群（英文）通常是致命的，但如果不是，它通常會導致不育的兒童。
- XXYY 症候群（英文）會導致男性兒童（由於兩個 SRY 基因）經常經歷性腺功能減退，需要補充睪固酮，但在其他方面看起來像典型的男性。
- 鑲嵌現象是指由於妊娠期間基因組突變，體內某些細胞具有一組染色體，而其他細胞具有另一組染色體。這可能是 XX/XY（導致兩套生殖器）、X/XY（斯威爾或特納症候群的輕度形式）或 XX/XXY（克林費爾特症候群的輕度形式）。
- 嵌合體發生在兩個受精胚胎融合成一個合子時，導致孩子的一半包含一組 DNA，另一半包含另一組 DNA。這可能導致一個在其他方面完全典型的男性或女性表型的人，甚至能夠生育後代，但在核型檢測中，根據其身體上的採樣位置，其結果與表型不符。在極少數情況下，這可能導致兩套完整的生殖器官。
- 先天性腎上腺增生症（CAH）是由於腎上腺過度活躍導致 XX 兒童的女性生殖器男性化。
- 雄激素不敏感症候群（英文）（AIS）是指對所有雄激素的全部或部分抵抗，阻止 XY 兒童除睪丸外的所有器官男性化。AIS 患者通常會發展出女性的性別認同，但有些部分病例可能是男性。
- 5α-還原酶缺乏症（英文）（5ARD）是指身體無法將睪固酮代謝成雙氫睪固酮 (DHT)，從而阻止生殖器男性化，直到青春期開始，孩子的陰莖才會突然長出來。
- 芳香酶缺乏症（英文）是由於睪固酮水平過高而導致原本是女性的兒童男性化（並且會在妊娠期間影響到母親）。
- 芳香酶過多症（英文）會導致原本是男性的兒童女性化，因為所有的睪固酮都會轉化為雌激素。
Open Ocean Exploration @RebeccaRHelm Friendly neighborhood biologist here. I see a lot of people are talking about biological sexes and gender right now. Lots of folks make biological sex sex seem really simple. Well, since it’s so simple, let’s find the biological roots, shall we? Let’s talk about sex...[a thread]
Open Ocean Exploration @RebeccaRHelm If you know a bit about biology you will probably say that biological sex is caused by chromosomes, XX and you’re female, XY and you’re male. This is “chromosomal sex” but is it “biological sex”? Well...
Open Ocean Exploration @RebeccaRHelm Turns out there is only ONE GENE on the Y chromosome that really matters to sex. It’s called the SRY gene. During human embryonic development the SRY protein turns on male-associated genes. Having an SRY gene makes you “genetically male”. But is this “biological sex”?
Open Ocean Exploration @RebeccaRHelm Sometimes that SRY gene pops off the Y chromosome and over to an X chromosome. Surprise! So now you’ve got an X with an SRY and a Y without an SRY. What does this mean?
Open Ocean Exploration @RebeccaRHelm A Y with no SRY means physically you’re female, chromosomally you’re male (XY) and genetically you’re female (no SRY). An X with an SRY means you’re physically male, chromsomally female (XX) and genetically male (SRY). But biological sex is simple! There must be another answer...
Open Ocean Exploration @RebeccaRHelm Sex-related genes ultimately turn on hormones in specifics areas on the body, and reception of those hormones by cells throughout the body. Is this the root of “biological sex”??
Open Ocean Exploration @RebeccaRHelm It means you may be genetically male or female, chromosomally male or female, hormonally male/female/non-binary, with cells that may or may not hear the male/female/non-binary call, and all this leading to a body that can be male/non-binary/female.
Open Ocean Exploration @RebeccaRHelm Biological sex is complicated. Before you discriminate against someone on the basis of “biological sex” & identity, ask yourself: have you seen YOUR chromosomes? Do you know the genes of the people you love? The hormones of the people you work with? The state of their cells?
Open Ocean Exploration @RebeccaRHelm Of course you could try appealing to the numbers. “Most people are either male or female” you say. Except that as a biologist professor I will tell you...
Open Ocean Exploration @RebeccaRHelm The reason I don’t have my students look at their own chromosome in class is because people could learn that their chromosomal sex doesn’t match their physical sex, and learning that in the middle of a 10-point assignment is JUST NOT THE TIME.
plant lesbian @alicemiriel @RebeccaRHelm As a fellow genetics lab teacher, this is the same reason my department stopped chromosome testing in lab. A really cool experiment would turn into guys getting freaked out they have XXY, etc.