A: Continuing with our class, today we are going to study briefly the miracle of life. Many of you may think you already know how babies come to be, but I am sure that some of the things that we will be talking about today may surprise you. Billy ，can you turn on the projector please? Thanks. Ok, does anyone know what this is?
B: Looks like a goat head to me!
A: Nice try, but this is a woman’s womb which contains her uterus and ovaries. The ovaries are packed with eggs and each month during the middle of the menstrual cycle, the ripest one will be sucked up by one of the fallopian tubes. This is called ovulation and the exact time of ovulation depends on the length of your cycle. In an average 28 day cycle, ovulation will most likely happen between the 12th and 15th days, counting day 1 as the first day of your last period.
B: That’s amazing! So each month, the woman produces these eggs and then waits for them to be fertilized?
A: Actually, every woman is already born with over four hundred thousand eggs! Some will start dying off immediately and others released during her fertile period.
B: What about the guys? I know they produce sperm and stuff.
A: That’s right! The man’s body has a tiny factory that produces sperm twenty four hours a day! Each ejaculation will release about a hundred million sperm so the factory is always pretty busy. The sole purpose of a sperm’s life is to fertilize the woman’s egg.
B: So, then we basically need to put one-and-one together so we can have babies right?
A: Yes, the man will have an orgasm during intercourse and ejaculate sperm and semen. Now this is where the race begins and all those millions of sperm will race and swim from the cervix, through the uterus to the fallopian tubes. This could take anywhere from forty five minutes to twelve hours! Not all of them make it, since some go the wrong way and get lost or simply die. Many will actually reach the egg but only one will penetrate it and fertilize it. Once this happens, the egg instantly changes and creates a protective shield once the sperm is safely inside.
B: And then? That’s it?
A: Well, the egg will be fertilized within about 24 hours of its release. The genetic material from the sperm combines with the genetic material in the egg to create a new cell that will rapidly start dividing. The woman is not actually pregnant until that bundle of new cells, known as the embryo, travels the rest of the way down the fallopian tube and attaches itself to the wall of her uterus. Any other questions? Then let’s move on.
womb n.子宫
ovulation n.排卵
ejaculation. n.射精
embryo n. 胚胎
wall n.内壁
A: 现在继续我们的课程，今天我们要简要第学习下“生命的奇迹”。你们中的很多人也许认为你们已经知道婴儿是如何形成的，但是我敢保证我们今天谈的事一定会让你吃惊。Billy你能打开放映机吗？谢谢。有人知道这是什么吗？
B: 对我来说，看起来像个羊头。
A: 不错，这实际上是子宫，包括子宫和卵巢。卵巢上有很多卵子，在每月的月经期，成熟的卵子会从输卵管留出。这叫做“排卵”， 排卵的时间取决于你的生理周期。在平均28天一个循环中，排卵最可能发生在第12天至第15天，上次排卵结束的那天叫做第1天。
B: 很令人惊奇。每个月，女人都能产生卵子，然后等待卵子成熟吗？
A:事实上，女人出生时就有4百万卵子，有些会马上死掉，其他的会在成熟期排掉。
B: 那男人呢？我知道男的会产生精子和精液。
A: 是的，男人的身体有一个微型的工厂，它24小时都在产生精子。每次射精会释放1百万精子，所以那个工厂相当忙。精子的主要用途是为卵子授精。
B: 那只需要将精子和卵子一配一就会形成婴儿？
A: 是的，男人在做爱中会有高潮，会射出精子和精液。现在这就是种族起源的地方，这些百万个精液会在子宫颈中赛跑和游泳，经过子宫到达输卵管。这个过程大概从55分钟到12小时不等，并不是所有的精子都能到达，有些会走错路，迷路然后死掉。大多数精子会到达卵巢，但是只有一个精子会结合卵子并授精。这个过程一旦发生，卵子马上会发生改变，一旦精子安全地在里面，卵子会形成保护盾。
B: 然后呢？这就完事了？
A: 卵子在24小时内授精。精子中的基因和卵子中的基因结合形成新的细胞，细胞迅速开始分裂。在形成胚胎前，女人实际上并没有怀孕，胚胎会进入输卵管并附着在子宫的内壁上。还有别的问题吗？我们继续。
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