Suppose you're running a startup and you have 12 employee-months worth of runway left before you'll need to show a concrete proof point to close the next round of funding or, preferably, get to cash-flow breakeven/Ramen-profitable.
Your product is inherently labor-centric. Your employees/team-mates are your best and only hope to produce the product.
In that situation, would you rather be using your last 12 person-months of runway paying your employees to work on the product or paying them to not work on the product and instead raise their own infant child?
Would your company be materially less likely to succeed if one of your employees had a new child and took 15-30% of the remaining runway while providing no benefit to the product? Probably.
What's the mechanism by which a company would be financially ahead with such policies? Would you personally be willing to work for less pay in order to work at such a company? I can agree that employees who use such policies might be much more likely to stay, but I wonder if employees who carry the load while the new parent is on leave (but their position not filled, so all the burden falls to the rest of the team) might be less loyal?
I'm a parent of 2; my wife took the statutory maximum FMLA leave with each of them; her employer had a generally generous paid leave policy, and I'm not anti-kid by any means. I am anti-regulation in general though...
These policies may be breakeven or profitable in the long-run; I don't know. I do know they present a period of unprofitability in the short-term. And when they are gender-specific or even primary-provider-specific, they can manifest themselves as hiring biases against those people most likely to use the policy.
If you only have 12 employee-months of runway, then you should not plan such that you need the whole thing. Parental leave is not the only uncontrollable circumstance that could be disastrous for your company. Your lead developer could get colon cancer. Your salesperson could jump ship without notice. Your co-founder could embezzle 20% of the investment capital. A patent troll could shake you down.
It boils down to a rather simple question. Would you rather fail with your ethics intact, or get money-rich by being an asshole?
Having a child is very much like that. The employee is on an extended sick leave, and then they're back and can be brought up to speed again. The big difference is that you know of this several months in advance and have every opportunity to make up for it and can take the time to train a substitute.
This is a good argument to treat parental leave just like other sick leave and leave it to a similar insurance system.
(To those to think companies' fear of children is rational, do you also think to ask your employees if they scuba dive, or ride a motorbike? That's probably more "dangerous" to the company than being of child bearing age, and the consequences far worse.)
Having had kids (and being aware of the law and I'd like to think not an utter asshole), I'd sanction anyone on my team who raised such a concern in a hiring discussion, but I'm quite sure that it happens all the time.
Even with a policy, there would be a rational/economic basis for bias against a mid-30s newlywed (of either gender) as opposed to a fresh college grad, or a married father of 3.
Your best control/counter against such a bias is that great developers are extraordinarily valuable, and so if I knew I could get someone great, as opposed to minimally bar-clearing, I'll wait through multiple paid parental leave terms...
Drawing from a deeper talent pool; building a more loyal workforce; improving morale. All of which help your existing hours be more effective and the latter two mean staff are more likely to do extra work.
It is to your colleagues, to the founders, and to the investors, all of whom have a significant vested interest (no pun intended) in seeing the company succeed and have all taken various kinds of risks to invest in the company and product.
Simply put: the product/company will be feeding my family in the success case.
If the cost of carrying an employee -- not a cofounder! -- for three months (how much is that? 50K? 60K?) is going to kill the startup, you a) probably shouldn't have hired the person to begin with and b) don't have much of an startup to begin with.
It's continually amazing to me how, in a capital environment awash with cheap funds and outrageous valuations, this kind of cheapness pervades everyone's thought processes. Stop thinking like broke college students, and start thinking like the people of substantial affairs you claim to be.