Paradigm
Here is the paradigm for the third person personal pronoun, singular and plural.
| case | masculine | feminine | neuter |
| subjective | he | she | it |
| objective | him | her | it |
| subjective | they | they | they |
| objective | them | them | them |
As you can see, English does not inflect the pronoun in the plural according to gender. It doesn't matter whether you are referring to boys, girls, or houses, you refer to them as "they" and "them."