Promoting girls and boys
Gender research over a few decades has been very productive. Mainly the disadvantaging of girls in math and science subjects has been emphasized and scientifically analyzed.
Successful teaching means lessons for both - boys and girls
In her dissertation Sylvia Jahnke-Klein has made suggestions for meaningful math lessons for both boys and girls. She has summarized her results in the following diagram (mouse-click for larger image):
The central elements of good lessons are not gender determined. They concern contents and methods which correspond in many ways with the intentions of the Fibonacci basic patterns.
Less emphasis on gender differences
Hannelore Faulstich-Wieland summarizes a typical teacher’s prejudice:
Girls are industrious, but uninspired – Boys are lazy, but ingenious.
At the same time she is strictly against gender-related ranking. Gender-linked observation runs the risk of emphasizing prejudice instead of abolishing it. Support should focus on the individual person with all his or her strengths and weaknesses.
Additional literature
Expertise "Mädchen und Naturwissenschaften in der Schule" von H. Faulstich-Wieland 
"Bildung und Geschlechterordnung in Deutschland" von W. Cornelißen
Jahnke-Klein, S., Sinnstiftender Mathematikunterricht für Mädchen und Jungen. Baltmannsweiler: Schneider-Verlag Hohengehren 2001