And now a dose of reality:
Child marriage - Wikipedia, the free encyclopedia
Lower legally allowed marriage age does not necessarily cause high rates of child marriages. However, there is a causative correlation between restrictions placed by laws and the average age of first marriage. In the United States, per 1960 Census data, 3.5% of girls married before the age of 16, while an additional 11.9% married between 16 and 18. States with lower marriage age limits saw higher percentages of child marriages.[7] This correlation between higher age of marriage in civil law and observed frequency of child marriages breaks down in countries with Islam as the state religion.
In Islamic nations, many countries do not allow child marriage of girls under their civil code of laws. But, the state recognized Sharia religious laws and courts in all these nations have the power to override the civil code, and often do. UNICEF reports that the top five nations in the world - Niger (75%), Chad (72%), Mali (71%), Bangladesh (64%), Guinea (63%) - with highest observed child marriage rates are all Islamic majority countries.[2]
Yes, though I already pointed out that those countries were amongst the highest - not Saudi Arabia or Iran. Those countries are also extremely poor.
If you go to the article that is linked to your quote, it shows how poverty is strongly causitive:
http://www.unicef.org/sowc09/docs/SOWC09-CountryExample-Mali.pdf
What Sharia law mandates child marriages?
Note - most of these marriages are not young children as you keep going on about, they are teenaged girls.