And you haven't answered my question - what if your entire team was made up of lone parents? What would you do then?
Most things don't come up suddenly. Christmas, school holidays etc. If an employer isn't allowed to check these things before they employ you (and it is fair that they aren't) then the team have to decide, individually, if they can continue to do that particular job. Just as people without a car can't live rurally with no buses and take a job in the city that takes 3 hours to walk to, and expect the company to fix their transport problem.
And if the entire team are single parents, I'd expect them to support each other at times when something comes up suddenly, or take fair turns with Christmas etc.
But parents of young children DO need more flexibility than others. Some people don't NEED flexibility at all, but just want it.
It is not up to your team mates to fix your childcare problems or to expect them to take on extra hours/workload because you can't organise childcare. That is a you problem, as they say. The Government could help out, and good employers do offer flexibility - to everyone. Your "right" to attend a nativity play does not trump my "right" to visit my mum on her 90th birthday, as an example. And in the past when that kind of thing has cropped up in teams I've worked in the one-off of a child's wedding or granny's 100th has been covered and if the nativity play can be covered too, all well and good, but it wasn't a given.
If parents of young children (or people with other relevant issues that require flexible working) are prioritised for flexible working, then people with no children/other commitments can still work.
Unless and until those getting flexibility because of, say, children, accept that those putting in the extra hours, sucking up the extra work etc are given priority for salary increases and promotions, flexibility has to be an all or nothing thing for me.
When i had young children and bust a gut to make a career at my work, i was always first in, last out, paid a wedge of childcare to allow that to happen, did the weekends when necessary etc etc. i was turned down for promotion because "as a mother you'll never be as loyal to the company". Which is when i basically worked to rule for the rest of the year. And just shrugged everything off. That is the reality of many workplaces.
Whereas if literally everyone has to have the same options - either everyone has the option of flexibility, or nobody does - then often nobody will be given the option.
Bollocks. My company offers flexibility. My friend who works for a massive German manufacturer says that people literally work their whole lives there because of their work practices. Both companies massively successful.
It is the same thing as if a company has 30% female board members they are more successful. Companies see these things working, and adopt best practice.
As i said above: we should all be fighting for all of us.