I feel more at ease to make friend with female rather than male. I believe it is because of my upbrining, especially during my childhood.
In elementary school, I went to Islamic school where boys studied in one classroom while girls studied in another room. Girls had to wear veil and long dress to cover their bodies. They were not allowed to enter the boys' room, and on the other way around. Our teachers told us strictly that it was HARAM to be close to the opposite sex, moreover to touch them, and more than that. FYI, HARAM means if people do it, they will get punishment from God, while they will get reward from God if the don't do it.
As far as I remember, my teachers taught us that God does not only have merciful and loving character, but also cruel coz of the existence of hell. And my teachers imposed the punishment more than the reward we would get from God, I suppose, so we were frightened to do those things considered HARAM.
The strict rule--and the threat of the extremely hot fire in hell--really mde me feel uncomfortable to make friend closely with boys. As a result, I only made friends with girls. I had a chat with boys too, of course, but I didn't dare to do more than that, moreover to have a close relationship with boys.
It continued until I was in Junior High School. At that time, I had some close friends who were all girls. I really didn't feel secure to make good friends with boys.
In Senior High School, I experienced a bit different thing. I majored in 'Bahasa' (Language) in which there were only two boys and two girls in one class. I was close to both of those boys, confided in them too about some personal problems of mine.
In my bachelor degree, again I didn't make good friend with boys.
I didn't have many boyfriends either before marrying my only daughter's father. I believe that it was really caused by the strict rule I got when I was in elementary school. Besides the "myth" saying that a girl who has many boyfriends is not a good girl. And it really hanuts many girls' mind. (They are really afraid to be considered by society that they are bad girls only coz of having many boyfriends.)
In my master's degree, there were 13 students in my major, 2 men, and 11 women. And, again, I only made good friends with the girls.
Indeed, until now, I still cannot make good friend with guys.