令人討厭的情人——同性戀的生物學解釋

譯自2003年12月3日美國《紐約時報》 作者：尼古拉斯D克瑞斯特 首發於光明觀察，轉載請註明譯者及出處；本譯文僅供參考，引用請查對原文。 光明觀察編者按：同性戀一向是達爾文理論的難題，本文介紹了關於這種性現象的幾種假說，可資參考。作者表面上探討科學理論，其實更有意為任何性傾向的社會群體申張他們應當得到保障的基本人權。副標題為編者所加。 最近我寫了一篇專欄文章，指出有越來越多的證據表明，同性戀有其生物學上的基礎。於是，又多了一個理由說明我們不應該根據人們喜歡誰而歧視他們。 結果，對同性戀婚姻（尤其是男性之間的）感到驚駭的讀者對我大發雷霆，他們指責我在捍衛可恥的行為而褻瀆了神靈，因為有案可查，上帝就公開譴責同性戀。他們毫不介意《聖經》上其他的建議，比如應該用石頭砸死那些在安息日出工的人們（《聖經·民數記》15:35），還有對毒打奴隸的暴行應當寬恕，因為奴隸是主人的財產（《聖經·出埃及記》21:21）。不知何故，似乎銘刻在石頭上的只有反對同性戀的文字。 然而，令人驚訝地是，很少有讀者提出一個最顯而易見的問題：如果同性戀現象部分出於遺傳，為什麼會有那麼多同性戀者？ 畢竟，同性戀者一般被認為較少可能會尋求異性伴侶——也就是用來遺傳基因的行為。因此，如果存在與同性戀相聯繫的基因（這一點仍未證明，但似乎越來越有可能），那麼它們又是怎樣被遺傳到今天的呢？ 科學家們已經提出了一大套理論。其中一個說同性戀者在生孩子方面可能不是生殖力旺盛的人，但是他們看護著自己的侄子和侄女，使他們避免受到劍齒虎（saber-toothed tigers）等意外的傷害，這樣有助於確保自己近親的基因能夠存活下來。 另一種理論則說同性戀者有著異乎尋常的強烈的性驅動力。雖然這種動力的大部分消耗在非生殖力的莽撞行為中，仍有足夠的留給男女兩性伴侶，使遺傳基因得以傳遞。兩種理論在很大程度上都受到了貶低。 一條通往更精深理論的線索在其他靈長類動物那裡。包括象倭黑猩猩這種人類的近親動物也經常大搞同性戀，很明顯那是它們結盟的一種方式。倭黑猩猩通過對其他同性夥伴的口交行為來求得對方的歡心，儘管它們也不會放棄任何與異性夥伴進行交配的機會。 對於倭黑猩猩——也許還有我們穴居的祖先，同性戀的性傾向通過得到群體首領的照顧和保護，而獲得了達爾文理論意義上的優勢。但是這種模式對倭黑猩猩比人類男性更適用：倭黑猩猩基本上不是異性戀就是雙性戀，而一些人類男性似乎格外地專註於同性戀（一些學者稱男性同性戀比女性的要多）。 因此一些學術期刊上的文章推測，有幾種基因可能與同性戀有著鬆散的聯繫。當所有這些基因匯合，也許再加上其他因素（如子宮內（womb）男性荷爾蒙激素的異常水平也會起作用），某些人可能就會成為同性戀者，並且不太可能遺傳這些基因。 這一理論接著說，在更常見的情況下，這些可能導致同性戀的基因只會呈現一兩個，這時它們產生出的就不是同性戀者，而是相對敏感、溫順、能夠體諒他人情感的異性戀者。這些性情能夠幫助他們找到配偶。因此，這些基因由於擁有基因學意義上的優勢而得以增殖。 當然，這些理論繼續下去還會更複雜，但是我希望宗教上的保守派分子深思這個問題：如果同性戀完全違背上帝的準則，它為什麼會深深紮根在人類以及動物王國的其他物種之中？（嚴肅的學術期刊文章已經描述過作者所推斷的雌性同性戀海鷗。） 批評家們過去總認為同性戀者收養的孩子最後也會變成同性戀。但是有越來越多的證據表明，同性戀者收養的孩子最終成為同性戀的可能性並不比異性戀者收養的孩子更高。 這裡的底線在於，同性之愛乃是一件神秘的事情，它遠比聖經律令所涉及的內容更為微妙——正象不同種族之間的性愛所展現的那樣。1958年的一次民意測驗發現，96%的白人不贊成白人和黑人之間通婚（《聖經·申命記》7:3譴責種族間的通婚）。1959年，一位法官宣稱"萬能的上帝……沒有讓不同種族結合的意旨。"他批准了維吉尼亞禁止種族間通婚的法律。 有一天，我們將會認為反對同性戀婚姻是同樣愚蠢和過時的。沒有任何力量會比愛情更神聖了，如果一些人生來已經被編好了程序，註定要去愛與他同一性別的人，那麼這種感情怎麼就不是神聖的呢？在我看來，犯下褻瀆行徑的並不是那些想與其他同性共享生活的人，而是所有那些專橫到抵毀愛情的人。 附：原文及網址： http://query.nytimes.com/gst/abstract.html?res=F20E10FF345E0C708CDDAB0994DB404482 Lovers Under the Skin By NICHOLAS D. KRISTOF Published: December 3, 2003 E-mail: nicholas@nytimes.com Recently I wrote a column arguing that there is growing evidence that homosexuality has a biological basis,and that this is one more reason not to discriminate against people on the basis of whom they love. The result was a torrent of fire and brimstone from readers who are aghast at gay marriage, and who accuse me of blasphemy for defending vile behavior that they say God is on record as denouncing. Never mind that the Bible also advises that people who work on the Sabbath should be stoned to death (Numbers 15:35) and condones the beating of slaves "since the slave is the owner"s property" (Exodus 21:21). Somehow it"s only the anti-gay bits that seem engraved in stone. Yet surprisingly few readers raised the most obvious question: if homosexuality is partly genetic, why are there so many gays? After all, gays are presumably less likely to engage in heterosexual pairings - the behavior that passes down genes. So if there are genes linked to homosexuality (which is still not proved, but seems increasingly likely), then how have they been passed down to our day? Scientists have offered a range of theories. One is that gays might not have been fecund baby-producers, but that they guarded their nephews and nieces from saber-toothed tigers and thus helped ensure the survival of closely related genes. Another theory is that gays have unusually strong sex drives, and that while most of this energy has been wasted on nonreproductive flings, enough goes toward male-female pairings that the genes are passed on.Both theories have largely been discounted. One clue to a more subtle theory is that other primates, including close relatives like the bonobos, often engage in homosexual behavior, apparently as a way of forming alliances. Bonobos curry favor by performing oral sex on others of the same gender, even though they also seize every opportunity to mate with those of the opposite sex. It may be that for bonobos - and perhaps for our cave-dwelling ancestors - an inclination to engage in homosexual sex conferred Darwinian advantages by helping to gain favor and protection from group leaders. But the pattern fits bonobos better than it does human males: bonobos appear primarily heterosexual or bisexual, while some human males (more than females, some scholars say) seem hard-wired to be exclusively gay. So some journal articles speculate that several genes may be loosely linked to homosexuality. When all come together, perhaps in conjunction with other factors, like unusual androgen levels in the womb (which also appear to play a role), the person may be gay and less likely to pass on those genes. But more commonly, so the theory goes, only one or two of these gene variants are present, and then they produce not gays but straights who are relatively sensitive, conciliatory and empathetic - qualities that help them find a mate. Thus these variants would be genetically advantageous and would proliferate. The arguments get far more complex, of course, but I hope that religious conservatives will ponder this question: If homosexuality is utterly contrary to God"s law, why is it so embedded in human biology and in the rest of the animal kingdom? (Serious journal articles have described supposedly lesbian seagulls.) Critics used to say that adopted children of gay couples would end up gay. But there"s growing evidence that children raised by homosexuals are no more likely to end up gay than those raised by heterosexuals. The bottom line is that same-sex love is a mystery far more subtle than just a matter of Biblical injunction - just as interracial love has turned out to be. A 1958 poll found that 96 percent of whites disapproved of marriages between blacks and whites (Deuteronomy 7:3 condemns interracial marriages). In 1959 a judge justified Virginia"s ban on interracial marriage by declaring that "Almighty God . . . did not intend for the races to mix." Someday, we will regard opposition to gay marriage as equally obtuse and old-fashioned. No force is more divine than love, and if some people are encoded to love others of the same sex, how can that be unholy? To me, the blasphemy is not in those who want to share their lives with others of the same sex, but rather in anyone presumptuous enough to vilify that love.
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