Is anyone else worried about asking for Flex time after their Maternity Leave?

I would like to work 4 days / week and 1 day / week from home if possible after my maternity leave. I would also be willing to drop down to 4 days / week and take a 20% salary cut and go to part-time status if working from home 1 day per week isn't possible.

I am worried about asking for this "benefit" though with the state of the economy. Why would they keep me when they could easily find someone (male) without kids who would be willing to put in longer hours to do the same job? I work in finance / accounting so I am worried...

What would you do? Any advice?