200803 Handedness

1. If you know an older left-handed person, chances are they had to learn to write or eat with their right hand. And in many parts of the world, it's still common practice to force children to use their “proper” hand. 2. Even the word for right also means correct or good, not just in English, but many other languages, too. But if being left-handed is so wrong, then why does it happen in the first place? 3. Today, about 1/10 of the world's population are left-handed. Archeological evidence shows that it's been that way for as long as 500,000 years. And despite what many may think, handedness is not a choice. It can be predicted even before birth based on the fetus's position in the womb. 4. If your father was left-handed but your mother was right-handed, you have a 17% chance of being born left-handed, while two righties will have a left-handed child only 10% of the time. Handedness seems to be determined by a roll of the dice, but the odds are set by your genes. 如果你认识一个年长的左撇子，很有可能他们过去必须学会用右手写字或吃饭。在世界上很多地方，强迫孩子使用“合适的”那只手仍是一种常见做法。 尽管表示“右边的”这个单词——不仅仅是在英语中，还有许多其他语言——同样表示“正确的、好的”。但如果作一个左撇子是错误的话，那起初为什么会出现左撇子？ 现今，全球约有1/10的人口是左撇子。考古证据显示早在50万年以前就已经是这样了。不管人们如何看待这件事，用手习惯是无法选择的。基于胎儿在子宫中的位置，用手习惯甚至可以在出生前就被预测出来。 如果你的父亲是左撇子，母亲却是右撇子，那你有17%的可能性成为左撇子，然而两个右撇子生出一个左撇子的可能性只有10%。用手习惯看似是随机决定的，但是几率受基因左右。