Marijuana/coffee and being pregnant

I've been reading a lot of these posts about marijuana. I've seen a lot of women tell other women that they are selfish risking their babies health since there is no proof or evidence whether marihuana does any harm to a fetus. And mad that these women take this risk. But I was recently looking up drinking coffee while pregnant. Literally it says the same thing. There's no proof or evidence what harm coffee does to a fetus. But it's overall exceptable, and I see the same women telling others that 200mg a day is fine. Even if they go over that, they tell them they should be okay. No harm done. Caffeine is a drug and the affects of it are unknown. But people are not considered selfish by drinking it. Would you do both? Are view both as selfish? Do you feel one is more safe than the other?