Yeah, this is completely okay. No one is entitled to know what a baby's genitals are, and they don't have to follow gender roles. They don't have to wear pink and wear bows, they don't have to wear blue and wear shorts. This is completely harmless and completely considerate of what the baby could grow up to identify as, so what's the issue here? They're just not participating in heteronormative culture. They don't have to.