If I ran a company (or at least had input into their benefits), I would insist that the company implement a suite of adoption benefits for all employees.
Before I did that, I would institute a very simple policy:
Your birthday is a paid holiday. Period.
I’m not saying that you take can use vacation or paid time to take your birthday off. Your b-day is a separate paid day off. You say your birthday falls on a Saturday or Sunday this year? Take the Friday before or the Monday after. Just let H.R. know which one. Born on the Fourth of July or another holiday already recognized by the company? Same thing – take an extra day before or after.
Few days are more special than your birthday, so why waste it sitting in meetings or putting cover sheets on TPS reports?