Anybody have some writing tips?

Not sure how you want to allude to a baby. If you're alluding to a woman being pregnant, you could do it a more factual way (for use in contemporary, hard-line fiction, where flowery descriptions or images would seem out of place) by noting in (passing) description of your character some characteristics common of a newly pregnant woman. If you're into more image-intensive prose, maybe describe nature (a spring morning, etc.) or other things associated with newness. If you do this, I would try to avoid cliches ('a spring morning' actually being one of them).

If you actually mean to allude to an infant without mentioning that there is an infant present, maybe focus on physical changes to a household that would take place if someone where keeping a child there. Why would a bachelor have toys laying around? Etc.

Or, once again, go for symbolism. A foal, or other young animal, with the character empathizing with its mother. Something like that. A young mammal just learning to walk might be a little too-overused an image, but I'm sure there are plenty of other options.

If you add any detail to your question to clarify, I would love to offer more specific answers. Sounds interesting, though.