Fertilising these eggs for experimentation is forbidden in America.

美国禁止为实验用的卵细胞受精。

This increase in cAMP then activates the sperm, and lets them start swimming and searching for an egg to fertilise.

cAMP的增加会激活精子活力，让它们开始移动并寻找卵子受精。

(Female spiders can do this because they store sperm for a period of days or weeks before they use it to fertilise their eggs.)

（雌性蜘蛛之所以能这样做是因为她们能将精液存留数日或几周的时间，然后决定是否用其对卵子受精）。

The right-hand one was conceived in the normal way, by a sperm fertilising an egg.

右边的那个是以正常方式受孕的，由精子使卵子受精。

They know that sperm fertilises egg, and one cell grows to two, four, eight, and so on.

他们知道精子使卵子受精，一个细胞长成两个、四个、八个，等等。