op, I think the point though is when and where and how these comments were made. e.g. if you'd just had to leave work in a hurry because one of the children needed picking up from school because of illness and this caused irritation, then the comment has been made in a different context to say, having said the same thing without any provocation iyswim.
People can't give you accurate advice if you don't outline the context, because context is important, whether you think the comments were discriminatory or not.
If I had a member of staff (or indeed if I worked with someone) who was constantly taking time off for the kids, always on the phone to the nanny/childminder during work time, constantly having to run out at a moment's notice, I would think that perhaps their children impacted far too much on their actual working day and I would wonder whether a different type of job would suit them better. And yes, I would find it annoying. I might not say it because it's not pc to do so, but in those circs I don't actually think it's wrong to think it.
But that would be different from if I had an issue with mothers in the workplace in general, because lots of mothers manage to hold down a job and balance that with the kids without the one impacting too heavily on the other.
Also, you need to think about what you want to gain from this. Contrary to popular belief, discrimination is incredibly difficult to prove, but it also does not carry vast payout as we would like to think it might. So while you might want to bring a legal case, you need to consider:
How much it is likely to set you back financially and in terms of the emotional impact.
What you are looking to gain, be that financial/physical i.e. in terms of the person you are making the claim against.
And you need to think about how this is going to impact on you in the future. Fact is that once you take your employer to court you won't be able to continue working there. So you need to consider whether taking an employer to court will impact on your future employment prospects. Because rightly or wrongly, in some industries, it is very likely to do so. Is a potential few thousand £ worth making yourself unemployable and earning you a reputation as a troublemaker?
Sadly, these types of cases rarely have an actual positive outcome, because while the win is positive in the short term, unfortunately many employers are put off by the idea of someone who is prepared to take them to court..