It's really wonderful to see companies looking after their employees like this and taking steps to reduce gender bias, and to improve inclusivity when it comes to benefits.
As an individual who is not likely to ever have children however, I would feel rather jealous of my co-workers who got to take advantage of this benefit. Some sort of clause like: "... when they become a parent ... or when they work for the company for five years without becoming a parent." would help me feel included.
I really don't mean to diminish this awesome perk, it is obviously much more inclusive than the status-quo and I commend Etsy for implementing it!