"Khola Hassan says there is no difference between nikah mut'ah and prostitution 'There is no difference between mut'ah marriage and prostitution. There is a time limit on the marriage, and the mahr given as a gift [from the man to the woman] is the equivalent as a payment to a prostitute'...
"Critics of these informal marriages, both Sunni and Shia, argue they allow a person to have multiple sexual partners and are used as an 'Islamic cover' for prostitution or the exploitation of women, with men taking on multiple 'wives' for a number of hours.
"In these circumstances many of the formalities and parental permissions are dispensed with for the temporary marriage agreement."
Nikah mut'ah was widely practiced during Muhammad's days when Muslim men were travelling away from home on "business".