seven? this is the first time i hear of that number among all the lies attributed to the prophet's marriage to aisha. the most common number thrown around is nine.
this is another topic that has been debated a lot and is under a lot of speculation. turkish historian omer riza dogrul claims she was 17-18 years old when she was married to mohammed. recently, this has been mentioned again in the turkish media, too. im sorry the link is from a turkish news site but it's just to show that i am not making it up:
http://www.habertakimi.com/103086-Hz-Ayse-Evlendiginde-9-Yasinda-Degildi.html
omer riza dogrul (died in 1952) points out that aisha helped in the battles of uhud and badr which took place miles away from their homes. and if the claim that she married mohammed at the age of nine is true, she must have been seven or eight during these wars. aisha also says she was a "jariya" (young girl) not a "sibyah" (infant) when the al-Qamar surah was written (during their marriage).
historians Taqribul-tehzib and Al-bidayah report that Aisha died in 73 A.H. (after hijri) when she was a 100 years old. this makes aisha about 16-17 when she married.
omer dogrul says that the historian ibn sa'd either intentionally distorted the truth or is mistaken. this lead to many other islamic historians to copy the same mistake in their recountings (especially during the moorish period in which the islamic teachings have obviously been distorted a lot for their own benefits) and gave material for non-believers to object to islam.
now, if you ask my opinion, i would never approve of a marriage between a 16-17-year old and an older man or a man having 8-9 wives TODAY. but it was absolutely ordinary for people back in the day who lived for 40-50 years max to get married so early and have so many wives during such times of war and desperation. i believe all of us would do the same if we lived in that area at that time.