每個人都有「同性戀基因」嗎？：英語精讀講義

2 to 6 percent of people self-identify as having predominantly homosexual attractions 用詞

2% 到 6% 的人自認主要會受到同性吸引，

and while there are many social and political theories on why,

而對於背後的原因，雖然社會與政治層面有許多理論，

what does science say? 表達脈絡

科學又是怎麼說的呢？

Is being gay genetic and if so, 片語搭配

同性戀與遺傳有關嗎？如果有，

do we all have a gay gene?

我們每個人都有同性戀基因嗎？

In the 90s,

1990 年代，

two studies using the Human Genome Project 文化背景

兩項運用「人類基因體計畫」資料的研究

found that gay men have a higher number of homosexual relatives 文法

發現，男同志的同性戀親屬人數

compared to heterosexual men

比異性戀男性更多，

and that gay siblings have similar linkages on their X chromosome

而且同志手足的 X 染色體上有相似的基因連鎖關係，

showing a high level of genetic heritability.

顯示這種特質具有高度遺傳性。

A more recent study of 400 and nine gay siblings

較近期一項針對 409 名同志手足的研究

also found linkages

也發現了基因連鎖現象，

in a specific region of the X chromosome labeled Xq28

其中一處位於 X 染色體上標記為 Xq28 的特定區域，

and in another region of chromosome 8.

另一處則位於第 8 號染色體的某個區域。

Furthermore,

此外，

a 2014 analysis of 50 years of research

2014 年一項彙整 50 年研究成果的分析

found gay men are more likely to have gay brothers compared to straight men 片語搭配

發現，男同志比異性戀男性更可能有男同志兄弟，

and lesbian women are more likely to have lesbian sisters

而女同志也更可能有女同志姊妹，

further suggesting the traits are genetically linked and passed on. 講解

進一步顯示這些特質與遺傳有關，而且會傳給下一代。

But if homosexuality is in fact genetic, 表達脈絡

但如果同性戀確實是遺傳的，

doesn't this create a paradox?

這不就產生一個悖論了嗎？

While some gay people still have children,

雖然有些同志仍會生兒育女，

overall they have 80 percent less children than heterosexuals. 文法

但整體而言，他們的子女數比異性戀者少 80%。

So,

那麼，

wouldn't the genes not be passed down 文法

這些基因不就無法傳給下一代，

and eventually die out? 片語動詞

最終會消失嗎？

Well,

其實，

a recent UCLA study used epigenetics to propose that everyone has a gay gene, 片語搭配

UCLA 最近一項研究運用表觀遺傳學，提出人人都有同性戀基因，

but it's whether or not the attachment of a methyl group to specific regions of DNA 片語搭配

但關鍵在於，DNA 特定區域加上甲基的過程

is triggered and turns it on. 片語動詞

是否會被觸發，進而啟動這個基因。

Epigenetics is the study of how your environment can chemically modify your genes, 用詞

表觀遺傳學研究環境如何透過化學作用修飾你的基因，

like how a queen ant's nutrition and pheromones can chemically alter an ant embryo

例如蟻后的營養狀況與費洛蒙，能以化學方式改變螞蟻胚胎，

to either produce a soldier or worker ant 文法

使牠發育成兵蟻或工蟻，

based on what's needed for the colony.

視蟻群的需求而定。

The UCLA study used gay and straight male twins

UCLA 的研究以男性雙胞胎為對象，其中包括男同志與異性戀者，

and found that a specific methylation pattern was closely linked to sexual orientation.

並發現特定的甲基化模式與性傾向密切相關。

The model was able to predict the sexuality of men with 70 percent accuracy, 片語搭配

這個模型能以 70% 的準確率預測男性的性傾向，

but this data used a small subset of people 表達脈絡

但資料只來自一小部分受試者，

and there is some controversy around the research.

而且這項研究仍有一些爭議。

Ultimately, 表達脈絡

總而言之，

a specific gay gene has not been found, 文法

目前仍未找到某個特定的同性戀基因，

but scientific evidence does suggest that human sexual orientation is strongly linked to genetics 文法

但科學證據確實顯示，人類的性傾向與遺傳密切相關，

and tightly regulated at the molecular level. 片語搭配

並且在分子層次受到嚴密調控。

It's even been found that giving birth to a son 文法

研究甚至發現，生下一個兒子後，

increases the odds of homosexuality in the next son by 33 percent 片語搭配

下一個兒子是同性戀的機率會增加 33%，

relative to the baseline population.

這是相較於一般人口的基準機率而言。

If an older brother is from a different mother,

如果哥哥和弟弟是不同母親所生，

there is no effect seen.

就看不到這種效應。

This has led some researchers to believe that male pregnancy 講解

這讓一些研究人員認為，懷上男胎

triggers a biological mechanism

會觸發某種生物機制，

that affects the mother's successive births.

進而影響母親後續生下的孩子。

A meta-analysis also found that statistically 用詞

一項統合分析也發現，從統計上來看，

homosexual men have more older brothers than heterosexual men.

男同志平均擁有的哥哥比異性戀男性更多。

Another study found that women exposed to high levels of testosterone in utero 講解

另一項研究發現，若女性在胎兒時期接觸到高濃度的睪固酮，

have higher rates of being not straight. 用詞

她們成為非異性戀者的比例較高。

So,

那麼，

why does this happen?

為什麼會出現這種現象呢？

The gay uncle hypothesis 文化背景

「同志叔叔假說」

suggests that gay members of a family that don't reproduce

認為，家族中沒有生育的同志成員

still increase the prevalence of their family's genes

仍能提高其家族基因

in future generations

在未來世代中的出現頻率，

by helping to provide resources for offspring that they're related to.

因為他們會協助提供資源給與自己有血緣關係的孩子。

After all, 表達脈絡

畢竟，

it's not just survival of the fittest individual, 講解

適者生存的不只是最適應環境的個體，

but the fittest family.

還包括最適應環境的家族。

Studies also show that there are lower levels of hostility

研究也顯示，較低的敵意

and higher levels of emotional intelligence, 用詞

以及較高的情緒智商、

compassion,

同情心

and cooperation in gay men,

與合作性，都可見於男同志，

which may also increase altruism and survival in human groups. 文法

而這些特質也可能提升人類群體的利他程度與生存機會。

Another hypothesis

另一項假說

suggests that the genes for homosexuality are ultimately coding for attraction, 用詞

認為，與同性戀相關的基因，最終編碼的其實是性吸引力，

meaning female relatives of gay men who share this same gene

也就是說，與男同志共享這種基因的女性親屬

will also have stronger attractions to men

也會更強烈地受到男性吸引，

providing an evolutionary advantage. 用詞

從而帶來演化上的優勢。

And studies have shown

而研究已經顯示，

that these females have more babies on average. 片語搭配

這些女性平均會生更多孩子。

The same would be true of lesbians 片語搭配

女同志的情況也是一樣，

and their straight male relatives.

她們的異性戀男性親屬亦然。

The famous scientist

著名科學家

E.O. Wilson once said,

E.O. Wilson 曾說：

"Homosexuality

「同性戀

gives advantages to the group.

能為群體帶來優勢。

A society that condemns homosexuality 表達脈絡

一個譴責同性戀的社會，

condemns itself."

其實是在譴責自己。」

Historically,

歷史上，

science has not been kind to the queer community. 講解

科學界並沒有善待酷兒社群。

In the past,

過去，

it was generally accepted 用詞

人們普遍認為，

that the brains and bodies of homosexuals

同性戀者的大腦與身體

were presumed to be of lower status

都較為低等，

with a popular belief that homosexual behavior

而且普遍相信，同性戀行為

was the result of defective development. 用詞

是發育缺陷造成的結果。

Even some LGBTQ2S people 文化背景

甚至有些 LGBTQ2S 人士

fear that this scientific research

擔心這類科學研究

could "other" the community 用詞

可能會把這個社群當成「異類」，

and be used to exploit or hurt people.

並被用來剝削或傷害人們。

Even from the available research,

即使只看目前已有的研究，

it's clear

也很明顯，

that most studies only focus on gay men 表達脈絡

大多數研究只聚焦於男同志，

and neglect other groups.

卻忽略了其他群體。

But more research

但進行更多研究

on the genetic and epigenetic factors

探討遺傳與表觀遺傳因素

of homosexuality

如何影響同性戀，

will decrease homophobic laws around the world

將能減少世界各地帶有恐同色彩的法律，

by further proving

因為這些研究會進一步證明，

that being gay is not a choice.

身為同志並不是一種選擇。

But could we ever

但我們是否有可能

genetically get rid of homosexuality? 片語動詞

從基因層面消除同性戀？

Watch our second video

請觀看我們的第二支影片，

where we discuss if it's possible

我們會在其中討論這是否可能，

and the implications of continued study

以及持續研究

into this field.

這個領域可能帶來的影響。

And subscribe

也別忘了訂閱，

for more weekly science videos every Thursday.

每週四收看更多科學影片。