"Now Jacob took for himself rods of green poplar and of the almond and chestnut trees, peeled white strips in them, and exposed the white which was in the rods. And the rods which he had peeled, he set before the flocks in the gutters, in the watering troughs where the flocks came to drink, so that they should conceive when they came to drink. So the flocks conceived before the rods, and the flocks brought forth streaked, speckled, and spotted. Then Jacob separated the lambs, and made the flocks face toward the streaked and all the brown in the flock of Laban; but he put his own flocks by themselves and did not put them with Laban’s flock." - Genesis 30:37-40
This is a particularly popular event for atheists to attack. In their eyes, this indisputably proves that the Bible is ignorant of genetics. Obviously, setting rods before sheep isn't going to affect the offspring's colouration, and so this story shows that Genesis is just some bronze age fairy tale.
What this actually shows is the way in which atheists love to cut the Bible in pieces when it suits their desires. Reading on, we see that God is actually credited with prospering Jacob with regard to the sheep. Laban tried to cheat Jacob, but God did not want Jacob to be cheated, and so He ensured that Jacob got the better end of whatever deal Laban made with him.
It is possible that whatever Jacob did, he fully believed it would affect how the sheep bore lambs. It doesn't seem so, but nothing in Christianity suggests the Patriarchs were history's greatest scientists. But whatever Jacob did, and whatever he believed, we see that ultimate credit is given to God.
A major flaw in atheistic apologetics is that they often take the miraculous as if the Bible says it is the norm. Yes, a snake and a donkey spoke in the Bible, but the Bible does not say snakes and donkeys talk. Yes, the Bible says Jesus was born of a virgin, that does not mean the Bible says virgins normally give birth. Yes, the Bible says Jesus rose from the dead, that does not mean Christians should expect people to just get up and walk after being brutally executed. Healing without medicine, duplicating fish out of nothing, creation ex nihilo, these are not things the Bible says are normal. The whole point of miracles is that they are not normal. In fact, a lot of the time, these miracles are the literary equivalent of God showing His passport.
So no, Christians do not read Genesis 30:37-40 and expect that peeling poplar rods will make any ewe that looks at them give birth to speckled lambs. Rather, we understand that God prospered Jacob, even in such difficult circumstances as being employed by a complete snake, and that Jacob, at best, did some things that he believed would have helped.
The atheist objection, therefore, is completely useless when you take the entire context into account. This is just one more example of atheistic cherry picking that can be easily refuted by reading. The question that must be asked, then, is why is this the kind of argument that exists? Why is it so hard to distinguish between an actual atheist argument and an argument made by Christians pretending to be atheists in order to make atheism look daft? Could it be because atheism actually is daft?