"I love my children."
Translation:Jag älskar mina barn.
Min is the singular "Min hund" "My dog" Because hund is an en word, you use min for the singular. Mitt is used if the subject is an ett word and also means singular. "Mitt äpple" "My apple".
Mina is plural. So instead of "Mitt barn" "My child" even though barn is an ett word it is "Mina barn" "My children" because mina is plural for all words, regardless of ett or en.