I've stayed at the same place but do a lot of recruiting. Hope an employer's perspective will help.
We interviewed a dad of 2 young children this week. He didn't put anything on his cv but at interview we were talking about the culture of the firm, how long people are expected to work and so forth (it's a law firm so not really 9 - 5). At that point he said he would come clean, he had 2 kids and the childcare deal was that generally he left the office at 5.30 to put the DCs to bed because his wife worked further away. We had then questions about how he would deal with entertaining clients in the evening etc, which he answered, and we talked about how he might need to pick up work after bedtime sometimes. We've asked him back for a second interview.
we also took on a mum who left her first firm when she was on maternity leave, and then came to us from that maternity leave to do a different and part-time role
I ask people about gaps on their cv every time. I think you need to explain them and honesty is the best policy in the long run, quite apart from legal problems about lying to secure a job.
I think it really depends on your area of work and whether there is a skill shortage. You can say that having worked with DC1, you know what it's like being a working mum and are comfortable about your ability to deliver the work to your employer. That should shut them up at interview; whether you get the contract is another matter, of course