Nested if and statements, I can't wrap my head around the syntax.

Hello all, I am new to Excel as of last night. I am working on a spreadsheet to keep track of my fitness, and I am trying to make an if and function that will look at cell "B3" for either an "M" or an "F" for male or female and then:

=IF((AND(B9>20,B9<24)),A3," ") for a male
=IF((AND(B9>18,B9<20)),A3," ") for a female

cell "A3" is the content in the Name field, and "B9" is the fat percent field which is listed numerically. If "B9" is in range it will display the name entered in the "A3" cell, if not, it will display a space leaving the cell blank.

I figured out how to get what I wanted out of this equation:

=IF(B3="M",(G3*1.082)+94.42-(B6*4.15),(G3*0.732)+8.987+(A6/3.14)-(B6*0.157)-(C6*0.249)+(D6*0.434))

but for the life of me I can't get my head to work around my present problem. If anyone can help me I would really appreciate it.

Kevin