To my better bloody soon to be born baby:
There are lots of sappy letters out there from about to be moms to their unborn son or daughter; this isn't one of those. I'm your dad and I'm supposed to toughen you up (or at least that what stereotype dictates right?).
First of all, the cat bites and will probably try to sit on you. The recommended course of action is to cry for mommy.
If you go outside, no matter what time of year, you'll get bitten as well. Either by the cold or by the mosquitos if you're lucky. If you're unlucky, or stupid (family history dictates both, as your dad and uncles have proven many times), you're also liable to get bitten by a consortium of other things including geese and swans (both are plentiful right outside the house), and a variety of mammals and insects.
The world is also full of people who are completely nuts. Your one grandpa will happily feed you frozen bread with a half-raw half-burnt egg and call it breakfast. As for your other grandpa... actually, you're probably not ready to be informed of him (I would recommend a course of general avoidance). Although, unhelpfully, these type of people are also, usually, the most fun.
The dog is friendly but also the definition of useless. If there's anything remotely scary, from a mattress to a wheelchair, she hides behind your currently still pregnant mom. She's likely not of more use to you. Oh, and she might knock you over out of excitement once you start to learn how to walk.
Don't believe anything anybody tells you. Especially if it's your dad. Especially during board or video games; consider this your one and only warning (even your mom won't be able to help you here). This also means don't do as I say or do as I do. Rather, do as your mom says and does; if daddy (or grandpa) promises you $20 for catching one of the aforementioned swans barehanded, it's not worth it.
For some time (probably at least two decades), you're going to have very poor decision-making skills. By all means, make a social media account, but just message your friends privately. If you post publically, don't be surprised if your dad or great-grandpa is trolling you in the comment section.
Dad is desperate to be cool but has no way, other than you, to keep up with the latest trends. If you start wearing pants around your knees and sideways hats, expect your dad to think this is the latest fashion and to do the same. The same goes for all the cool and hip words; your dad wouldn't want to be square.
Like all dads, yours is a phenomenal dancer and you're free to steal his dance moves.