I see assumptions being made here about choices to be with ones family or pursuing a career. The assumption seems to be that, whatever the career, you can automatically have both. It just isn't true!
Some careers just don't give that option. Assuming that employment law will allow this 'balance' in all careers is a fundamental mistake. Therefore you have to find the job/profression that allows you to find your work/family 'balance'. Don't choose a job and then expect the law to sort it out for you. That would be a business on a hiding to nothing!
Two part timers doing the job of one cost more than a single person in the same position - FACT! You can't avoid it - uniforms, administration, recurrent trainig etc etc. They cost more. The whole point of a business is to be competitve and make a profit - if it doesn't do that it doesn't last long. Therefore the business employing the part-timers, if it goes down the part-time employment route, is going to have to save money elsewhere. So something somewhere is lost to EVERYBODY. We ALL lose.
Those that think this case is a plus for workers are almost exclusively those who want part-time work themselves, and they always fail to see that it costs more! Somewhere everyone is losing something, however small. The losses accumulate and eventually people realise that things are not what they used to be ....... but they don't associate it with their desire for part-time work. It gets laid at the door of something else - rising fuel prices, competitors fares yada yada yada.
I am married, I don't have children ...... but I have a FAMILY. Would I like to work less and spend more time at home? Human nature probabaly dictates that it is thus ....... but I don't have kids, but somehow my family is treated as less 'deserving', I don't get the option of part time, assuming I wanted it in the first place. Is that fair?
No, this case is but a small detour in the inexorable decline of benefits for ALL employees as a whole. The folk that get their part-time or whatever think they are doing great. The load has to get 'picked up' elsewhere and eventually things are lost - benefits, salary increases, et-bloody-cetera.
With rights there are always responsibilities. The responsibilities need to be exercised FIRST, not the rights. But the innate selfishness of parts of human nature seem to allow the noisy selfish lobby to get their 'rights' first. It will come home to roost but unfortunately we ALL have to pay. By which time it is too late.