If someone takes parental leave, should that have an impact on the size of their next raise or the timing of their next promotion? I can think of three perspectives on this question.
"Parents shouldn't be given paid leave." Underlying this take is the belief that people are paid to work, dangit, and if you're not working you shouldn't get paid. Why should your coworker be paid to run off and have kids, leaving you to pick up the slack? You're already busting your butt – why should you have to subsidize someone else's family, too?
Personally, I think this is the least healthy take, bordering on self-destructive. Healthy families are the foundational units of a healthy society. They're where we learn our cultural and societal values, draw mental and emotional support, and learn basic behaviors like love, humor, and empathy. By supporting families, we support healthy societies, which benefits all of us. I think it's fair to view any policy that undermines the formation of healthy families as a societal malady.
"Parents should be given paid leave BUT their absence should factor into their rewards." This is the technocrat's perspective. It attempts to support those who have children without "penalizing" those who don't. Parents are paid during leave so they can focus on their child at a critical time, but the consequence is that their absence will delay their career growth. Consider a new parent who takes leave for 6 months. Under this policy, when it comes time for a raise they'll only be eligible for 50% of the raise that they would have gotten if they hadn't taken leave.
This take sounds rational but it ignores the human angle. Let's say the parent from our example is a top performer at their company. Knowing that those 6 months will be a speed bump in their career, do you think they'll be motivated to do their best work when they come back? I doubt it. And if they know every day on leave sets their career back, will they really be focused on being a parent? Nah, their mind will still be at work.
This approach is critically flawed because it offers a lose-lose choice to the parent: either take leave and come back under-rewarded and demotivated, or succumb to pressure and waive the benefits of leave.
"Parents should be given paid leave AND they should be fully rewarded." Personally, I love this approach. This is also how things work at Elastic. It encourages folks to take as much leave as they want and return when they're ready, while also recognizing top performers and motivating them to continue doing their best by rewarding them with the raises, promotions, and so on that they deserve.
What I like about this take is that it tears down the fallacy that taking parental leave somehow penalizes those who don't take it. If taking parental leave was the absolute winning strategy then everyone would take it. But that doesn't happen, because the experiences of cuddling your child, bathing and feeding your child, sleepless nights, warming bottles, pediatric visits, and doing lots of laundry and folding piles of tiny little clothes isn't for everyone.
This policy offers the most flexibility for both parents and non-parents because it caters to the fact that people have different goals in life. Who could argue with that?