YOU SAID:

i don't know how your mom ado

INTO JAPANESE

私はあなたのお母さんの養子様

BACK INTO ENGLISH

I am your mother's adopted child

INTO JAPANESE

私はあなたの母親の養子です

BACK INTO ENGLISH

I am adopted by your mother

INTO JAPANESE

私はあなたの母親に養子になりました

BACK INTO ENGLISH

I was adopted by your mother

INTO JAPANESE

私はあなたの母親に養子になった

BACK INTO ENGLISH

I was adopted by your mother