I have to part company here and say that expressing gratitude for being brought into the world (or for breeding) contradicts the 1st Noble Truth.
Sutras should be taken with a grain of salt. Test them, apply what works, and dispense with the rest. Don't hold anything as being worthy of veneration just because it's a Sutra. While many Sutras are profound, many are contradictory, incoherent or just plain nonsense.
So work it out for yourself. If life is Dukkha, then why be happy (and express gratitude) that you were brought into it? If (as some Buddhists claim) it's because it's an opportunity to practice, then ask if you'd feel similarly grateful to someone who broke your legs and thus gave you an opportunity to heal.
This isn't to say that we should harbor ill will because of this; it is what it is, and our energy is best spent making the most of where we are. But acting like we were done a favor by being thrown face first into Dukkha strikes me as disingenuous.
I believe this is the result of politics. At some point Buddhism needed to appeal to laypeople who had families, or to the politico/social order, and the result are teachings like this.
None of this is to say that laypeople can't benefit greatly from Buddhism.
Conclusion: Don't take anything seriously just because it's a Sutra.