Reference: Silsilah Kitaab ad-Da’wah (12), al-Fataawa – Volume 3, Page 189-90
Question: Some women dress their young daughters in trousers, and thereafter dress them up in an ‘abaa.ah (full-length outer garment covering a female’s body from head to toe).What is the ruling regarding this?
Response: That which I am of the opinion is that the young girls should not be dressed in trousers, since from one angle – this does away with their humility, and from another angle – there is a rule amongst the people of knowledge, [and that is] «whatever is haraam for the elder [female] to wear is [also] haraam for the younger [female] to wear»; [in that case], I am of the opinion that the young girl should not be dressed in trousers, even if she is covered with an ‘abaa.ah.