From TalonRO Wiki

As it is not easy to find loving parents for those who wish to play Baby characters, we have introduced Agatha's Orphanage. You will not have parents, but you will have a Baby character and various advantages which are explained below.

To become an orphan, you have to be a Level 1/1 Novice. This means you have to skip the Novice Grounds and head to the Orphanage right away. It can be found at Hugel 152,211. You'll see a Notice Board outside the orphanage.
Find the Orphanage at Hugel 152,211
Once you are inside the Orphanage, talk to the Orphanage Manager named Agatha in the back of the house. She will explain the advantages and disadvantages of being an orphan. You won't have any parents, but as long as you are lower than Level 70, you will have various bonuses such as free HP/SP healing, resting buffs and more.
Talk to the Orphanage Manager
An advantage of being an Orphan is that you can rest in the Orphanage. Resting is better than just using the Doctor as it's completely free and heals 100% HP and 50% SP. Furthermore it will give you a random buff to help you level up. Once you have rested, you wake up upstairs and you can talk to Agatha again to warp to one of the capital cities and start your adventure!
Resting at the Orphanage gives you various bonuses
Once you are a Baby, you will have various advantages. The first thing you can try is the Cook's Quest who can be found downstairs. For just 20 Fish Tails he can cook you a delicious meal that will make you healthy and strong.
Talk to the Cook for a quest
The next quest you can do is one of your sister orphans who you'll find upstairs. If you are Level 40 and bring her an Egg Shell, she can make you a special Orphan Egg Shell that is not obtainable in any other way.
Talk to one of your sister orphans for a unique headgear quest

Caution! Once you become a baby character, you cannot undo it. So be careful if that will be the gender/name that you will want for your baby character. You also cannot be adopted by real parents after you become adopted by the Orphanage.