Referring to a twin sibling

I am currently working through Genki 1 for practice and it wants me to write about my family.

I have a twin brother so referring to him with 弟 doesn't seem quite right since I never refer to him as being a "younger/little brother."

I see that 双子 means "twins" but jisho.org doesn't come up with any results for "twin brother" and google translate (I know its not great) gives me 双子の兄弟 which I interpret closer to "twin sibling" which could mean a twin brother or sister.

Would it be more correct to use 双子の弟 since we are twins and he is slightly younger than me?

We are also identical twins if that changes anything.

Thanks!