Question: are phineas and ferb twins?
Answer: They time-travel twenty years into the future, and Future Linda states that Phineas and Ferb are 30 then. Therefore, they are around 10 at present. ... Phineas is the same age as Ferb. The reason the boys are stepbrothers is because producers wanted them to be the same age, but not twins, and be more than just friends.