I got almost all info from Ushi no Tane. Its a harvest moon site and it has a lot of tips and help for Harvest moon look it up! :D (Can I just take stuff from other websites?)
On the second year you will have your one and only child. You can choose the gender of the child by talking to this pot at the harvest Sprites house in year one. After talking to it 100 times you'll choose if its a boy of a girl if you choose girl than you'll have one but if you dont choose girl theres no way you'll get one. Each child will have a different personality and looks. Sons will look like the mothers and the daughters will look like the father. (All girls look EXACLY the same)
Toddler Stage (Chapter 2)
In the beginning you can sway your child from its job choice buy giving it certain types of gifts and showing him/her to certain people. You can talk, pat your child on the back, toss it in the air and snuggle them. Certain children like different things. Since this the only chapter where you can take your child around town show it to people that will help his career.
You can only trigger one scene in this stage. You give your child a bath.
The Kid Stage (chapter 3) In chapter 3, your child gets its own bedroom and will look around 7 or 8.
You can Trigger one scene in this chapter. Your child will have found some sort of iteam like a box or a stick and they'll ask you if you think its cool
Teenage stage (Chapter 4)
Your Child is now a teen he looks like hes around 15/16
Theres one scene that you can trigger in this stage and its really wierd (And kinda creepy) You'll enter your child's room and Daachan (a teddy bear that you can buy from van) is walking around while your child is laying on the floor. The teddy bear will just fall and your child will stand up and say "get out"
Adult stage (Chapter 5 and 6)
Your child is now an adult and looks around 18-20. He or She has decided on what they will do and can not be swayed
there are two scenes that can be triggered
One scene is where you son wants to talk to you about love. He seems to have fallen for one of the girls in town, probably Kate. If you are married to Nami she'll walk in and tell him what she thinks. (I'm not sure what scenes trigger for girls) I think that if you have a daughter the same scene will happen but she probably is in love with Hugh.
In the other scene your son will offer to wash your back and he'll remember how much fun he used to have when you bathed him as a toddler. It makes him sad that you've gotten so old and thats he so mutch more stronger than you ever were.