What Causes A Dark Complexion?

i tested vdrl reative in my pregnanacy ,my baby got dark copmlexioned because of this.i am fair,my huband is fair,all members are fair.do u think it is possible because of vdrl?i m 28 yrs old,is it true conceiving on 14 days or 16days of period increase the chance of having a boy child?i have my periods 2 or 3 days before due date.is it any way to increase the chance of boy child.