Birthday wishes to a son should reflect personal sentiments and also serve as an inspiration for the upcoming year. One message to write to a son on his birthday is "My dear son, may your life be filled with happiness and sunshine not only today, but all year long."
Another birthday wish from a parent to a son is "On this birthday of yours, I have three wishes for you. First, I hope that this birthday teaches you something new and wonderful. Next, I hope that this day makes you smile as much as watching you grow has made me smile. And third, I hope for you that beautiful moments like this one come to you every single day. All my love!"