"We are their children."
Translation:אנחנו הילדים שלהם.
the word "ילד" refers to a young boy usually between the ages of 3 and 13. The word נער refers to young lads who range up to 18. In Hebrew if you refer to children as adults or any age you say בנים (sons, or children) בנות (daughters or female children). To refer to one child you say בן (m) or בת (f).
baby - תינוק/תינוקת, infant - פעוט/פעוטה (not in common use), child - ילד/ילדה (before his teens or up to the begining of the teenage, somthing like 3 years old up to 12-13 years old), teen - נער/נערה, we have a term that describe someone from the age of 18-19 up to about 25, thogh it's very uncommon, and is used, these days, mainly in literature - עלם/עלמה, young adult - בחור/בחורה, adult - בוגר/בוגרת, מבוגר/מבוגרת (depends on the subject), old - קשיש/קשישה, זקן/זקנה
An alternative way to say “their children” (or “their boys”) is ילדיהם yaldeihem but here you can’t say ילדיהם because that form comes later; shel- is being practiced in this unit.
The reason that there is a ה “the” in front of יולדים is because possessives are most commonly formed in Hebrew by saying, for example in this case, “the children of them”. “The children of them”= “their children”.
I think that if a couple have only sons or only daughters their children would say "אנחנו הבנים/הבנות שלהם" rather than "אנחנו הילדים/הילדות שלהם". Sincerely, I don't think I have ever heard daughters that said "אנחנו הילדות שלהם" (though an only child might say "אני הילדה שלהם"), but thechnically it is possible.
Family members such as mom, dad, brother or sister don’t need ה because they are already definite. The examples given in the tips and notes section, mom, dad, brother, or sister are all singular so that makes them definite.
The word children is not singular, so it is not definite, so it needs the ה.