还有染色体！！！
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
性染色体有远比XX和XY要多的组合，此类情况称作性别分化差异。它们并不会总导致间性状况，且许多人在青春期开始时才表现出来。
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XX男性综合征（46,XX Male）：精子减数分裂过程中，SRY基因在交叉互换中进入不含 Y 染色体的精子。精卵结合后即产生带有SRY基因的XX型胚胎，最终发育为有XX染色体组却表现为男性的孩子。
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斯威耶综合症（46,XY Female）：有XY染色体组的孩子表现为女性。很多种基因型都可能导致这种疾病，包括：
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XX特纳氏综合征：斯威耶综合症非常像，但其发生于有 XX 染色体组的孩子身上，导致卵巢功能丧失。
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特纳综合征（45,X）：导致多种异常的、表现为女性的孩子。其病因为精子的性染色体丢失。
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克兰费尔特综合征（47,XXY）：患者多为有更多的女性化特质的男孩子。在极少数案例中，患者出生性别为女性，致使发育出女性化的睾丸而非卵巢。
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49,XXXXY克兰费尔特综合征：往往是致死的，幸存的孩子基本不育。
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三X染色体综合征（47,XXX），四X染色体综合征（48,XXXX）和五X染色体综合征（49,XXXXX）：将使女婴具有愈发严重的健康问题。
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XXYY 综合征：由于携带双份SRY基因，表现为男性。常常会导致性腺机能减退，因此需要补充睾酮，但其余方面与一般男性相似。
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镶嵌现象：指由妊娠期突变引起的，体内部分细胞有一套染色体组，而其它细胞有另一套染色体组的现象。染色体可能是XX/XY（产生两套生殖器），X/XY（较轻微的斯威耶或特纳综合征）或XX/XXY（较轻微的克兰费尔特综合征）。
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嵌合现象：两个受精卵合并为一个胚胎，导致孩子一半细胞有一套DNA，另一半有另一套DNA。患者可能表现为典型的男性或女性，甚至保有生育能力。染色体核型分析取决于取样位置，而不一定与患者情况一致。在极少数案例中有两套完整的生殖器官。
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先天性肾上腺增生 （CAH）：肾上腺过度活跃导致XX孩子的女性生殖器男性化。
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雄激素不敏感综合征（AIS）：对雄激素部分或完全拮抗，导致XY染色体组的孩子睾丸外的所有器官都不会男性化。AIS患者性别认同常为女性，但部分案例认同为为男性。
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5⍺-还原酶缺乏症（5ARD）：丧失将睾酮代谢为二氢睾酮（DHT）的能力，这阻碍了青春期前的男性生殖器发育，那时会突然生长出阴茎。
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芳香化酶缺乏症：由于睾酮水平过高，导致女孩子男性化（睾酮还可以在妊娠期间透过胎盘屏障进入母体）。
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芳香化酶过多综合征：由于所有睾酮转化为雌二醇，引起男孩子女性化。
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.