If you call the baby an "it," there is a high probability that its parents will be offended and think you're a jerk. Generally, we use "it" for things, not people. So when you call a person an "it," you're being a little bit insulting by treating that person a thing rather than a person. New parents are not likely to think kindly of people who treat their child like a thing. You're much better off getting the gender wrong than calling the baby an "it."

He (yes) She (yes) It (no) It will be safer not to call a baby 'it'

Cuando es un bebé no hay distinción de género( masculino/femenino)

You can, but in general, as a native English speaker, you refer to babies with unknown genders as, "They", such as "How are they feeling?" Baby works fine, but I wouldn't use he/she generally.

The word baby is unisex, which means it can be used either on the male or female sex. The word baby means literally an infant or little kid regardless of their gender but it's also an endearment (like sweetheart or sweetie, etc) used on lovers, friends and family or someone you don't like as a sarcastic expression or even a loved pet why not.