'So let's say from the beginning man and woman was equal....what happens when a woman has a baby and breastfeeds?'
Well, some milk travels from her nipple into the baby. The baby therefore doesn't die but grows and lives. Is this somehow bad in a subtle way I'm missing? 
To be serious ... I am not quite sure how you get from that 'beginning' to 'workplaces', but I think your basic problem is that you say 'assuming' -it's probably easier to understand feminism if you start out not making assumptions, or questioning those you do have. If you do that, you can start thinking, 'wait a minute, what about all the kinds of work that do or have involve babies, or co-exist with babies and children... gosh, that's most of civilized society I've just described!'
Then you can think about how to tackle the issue of some workplaces today that aren't suitable for babies - if that's an issue that's central for you. Can they be made more suitable? Or will these always be jobs that rely on some kind of childcare? If the latter, how can childcare be properly valued?
I don't think, personally, these questions necessarily have anything much to do with separatism, though I can see that it might be helpful in some circumstances to think of them together (eg., if you're trying to think about how a separatist community would function economically). I think they're really just general questions - and there is a really good thread in this section about the value society accords mothers, if you're particularly interested.
I don't know about others, but what came out of this thread most strongly for me was the idea of separatism as a refuge. For me it wouldn't and couldn't be a permanent lifestyle - but each to their own.
Hope that makes sense - I was a bit confused by the questions but if you want I will try to clarify.