To legalise parents receiving entitlement to unpaid parental leave from day 1 of their employment contract. 
Why, you ask? 
Because parents cannot put their children’s illnesses, doctors appointments, dentist appointments etc on hold for 12 months.
And sadly if you have to request unpaid leave within these initial 12 months of your employment, it wrongly reflects poorly on the employee - leading one to be managed out before they even have a chance to reach 12 month entitlement mark.
Why would an employer choose to protect a parent (often the mother) who receives such support at 12 months, over someone who does not have children & therefore will not be entitled to such lengthy unpaid leave. Because they ultimately lose out on the employees productivity. (Or so it is incorrectly assumed.)

The 12 month law that currently stands essentially acts as a target to manage a parent out of the business before this point. Often having the probationary period extended, rather than passed. With the understanding that HR are aware it can take 3-4 months to typically manage someone out of the business on a performance program - to avoid ‘unfair dismissal’ claims in court. 
And although protected characteristics are automatically protected via the Equality Act - often the stress is too much, and the idea of a court battle when having to be parents at the same time, is too much to handle. Especially when the corporations usually have legal teams & HR advisors trained to carefully disguise their intentions through ‘performance plans.’ ‘Gross misconduct etc.’ 

This should be an automatic right for any parent within the UK - particularly the default parent. (Motherhood.) Especially if they have a child with disabilities. As their needs are more frequent & complex in nature, so they should have employment security - without the fear that caring for a disabled child could impact their career & chances at passing a probationary period - and meeting the 12 month instigation period for entitlement.

Too many parents - particularly single mothers are losing work due to being the default parent and not having the unpaid leave legal security from day 1 of their employment contract.

Such a change in the law could protect parents, and enable them to feel secure to take leave when needed for their children/ SEN children, without fear of retaliation. Without fear of their job being at risk from taking such necessary unpaid leave.