In the womb 2
Each month a woman’s ovaries(卵巢) release one egg that contains her own genetic code. She made these eggs while she still a fetus herself, nestled inside her own mother’s womb. And they’ve been kept in storage ever since, through childhood, adolescence and adulthood, ready to burst into life.
每个月女性的卵巢都会产生一枚卵子，卵子中含有她的遗传密码。当她在还在妈妈的肚子里是个胎儿的时候，她就开始产生卵子了。所以从那时起，卵子就开始被储藏起来，从儿童、少年一直保存到成年，最后才进入活动期。
How the sperm find their way to the egg is something of a mystery? Recent research indicates that sperm have a sense of smell and can sniff their way to the egg. The journey is so long and arduous for the sperm that only a handful survive. It may take up to ten hours before the actual moment of conception. The first sperm to reach the egg are the strongest and fittest, and the first to burrow(挖地洞) its head through the egg surface will be the winner. There are no prizes for coming in second. The instant one sperm enters the egg, it trigger a change in the egg’s membrane, making it impenetrable to all other sperm, which all die off within a week.
精子通过什么方法找到卵子到目前为止还是个谜。最新的研究表明精子有一种特殊的嗅觉功能，能帮助它们找到卵子。阴道里的旅行漫长而艰辛，受精之前精子可能要花费数十个小时才能完成这次旅行，所以只有很少一部分精子可以活下来。最先到达的精子都是最强壮和最健康的，而第一个用脑袋钻入卵子的精子才是最终的胜利者。落后的精子根本不可能再进入卵子，因为一旦有精子进入，卵子细胞膜就发生变化，其它的精子再也无法进入，并在一周内全部死亡。
Once within the egg wall, the sperm’s nucleus is drawn toward the egg’s. The two cells gradually and gracefully become one. This is the moment of conception, when an individual’s unique set of DNA is created a human signature that never existed before and will never be repeated. The genetic code is stored in these bundles called chromosomes(染色体), 23 from the mother and 23 from the father. Each chromosome is made of a tightly-coiled strand of DNA. This molecule, shaped like a double helix(螺旋), carries our genetic code. Each microscopic(显微的) chromosome contains over six feet of DNA. A pattern of chemical codes creates this twisting ribbon of DNA and holds the key to our uniqueness, our genes.
精子进入了卵子后，它的细胞核就会向卵子的细胞核移动，慢慢结合为一个，而两个细胞也变成一个细胞，这个过程叫做受精。这是制造一个人独一无二的DNA序列的过程，这个人从未在地球上出现过，而且将来也不可能被复制。基因密码储存在被称为染色体的带状物体上，其中23个来自母亲，23个来自父亲。每个染色体由很多紧密地连成卷的DNA分子组成。DNA分子的形状是双螺旋形，上面含有基因密码。每个染色体拥有超过六英尺长的DNA分子。某种形态的化学密码创造出了这种独特的扭带状的DNA分子，并且决定了我们基因的唯一性。
It takes between 20,000 and 25,000 genes to make a human, roughly the same number as a chicken. All of us have a complete set from each of our parents, deep in the nucleus of every cell in our bodies. Our genes are a set of instructions that tell us to become a human rather than a fish or a tree, as well as deciding exactly what kind of person we will be. Each gene or combination of genes is responsible for a specific trait—whether our baby girl will have her mother’s hair and strands or her father’s eye color and long fingers.Some genes will be dominant, others completely hidden, making each one of us physically and genetically unique. Our parents make an equal contribution to most of our genetic makeup. But the sex of the child is determined solely by the father. The 23rd pair of chromosomes has the specific job of determining sex. The sex chromosome that comes from the father could be one of two types, X for a girl, or Y, a much smaller chromosome, for a boy.
每个人含有20000到25000个基因，数量大概和一只小鸡含有的基因量差不多。我们每个人都从父母那里继承了双方完整的基因序列，它们就隐藏在我们身体的每个细胞里。基因是使我们成为人，而不是一条鱼或是一棵树的一组密码，同时它们也决定了我们将会成为什么样性格的人。每一个基因或者基因组都决定着我们身上的某个特征——比如这个女婴将拥有她妈妈的秀发，有着和爸爸一样的眼睛颜色和纤细的手指等等。有些基因是显性的，另一些则是隐性的，它们使我们无论在生理上还是遗传学上都是绝无仅有的。我们的父母对我们大部分的基因构成起着同样重要的作用，但是孩子的性别只由父亲的基因来决定。第二十三对染色体是决定性别的性染色体。来自父亲的性染色体有两种形态：女孩是X，男孩则是Y，一种更小的染色体。
An X sperm won the fertilization(授精) race for these parents and they are going to have a girl. The genes she’s inherited have already predetermined her looks and much of her character—whether she is stubborn, intelligent, a thrill seeker or good at music, and even her vulnerability to certain diseases like cancers, schizophrenia(精神分裂症) or diabetes. The exact course of her life will depend on such things as her friends, family and environment; but at the instant of fertilization, much of her future is predetermined.
一个含X染色体的精子成功受精后父母就会得到一个女孩。她继承的基因已经决定了她的相貌和她大部分的性格——固执、聪明、富有激情、或者爱好音乐等等，甚至是否容易患上某些疾病，如癌症、精神分裂症或者糖尿病等都已经被基因先天决定了。虽然她真正的生命之旅将如何进行取决于她的朋友、家庭和生长环境，但在受精的时候，她未来的很多特征已经被决定了。
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