The time depends and varies person to person. But most of the people will start having sex by the age of 17 or 18
exercise, good eating habits, sexual intercourse .
No. Can you get pregnant ever time you have sexual intercourse? Yes. Is there something you can do to decrease the risk of getting pregnant everytime you have sexual intercourse? Yes.
Does partial removal of foreskin increases time of sexual intercourse for men?"
It depends on your happenings....
You may still have a false negative but you are plenty of time after intercourse and you had intercourse at the right time to become pregnant.
The sperm is usually discharged during intercourse. That one of the prime reasons for intercourse: for male sperm to get into a female for fertilization of her egg(s).It depends on what you mean by "safe". It is the natural method of procreation.
It may take one time but not every act of intercourse results in conception
Having sexual intercourse at precise times so as not to coincide with ovulation (not very reliable) or not having sexual intercourse at all (100% reliable).
half n hour
That can not be so. The sex of the baby is not decided by the day of the intercourse.
Intercourse does not affect your period unless you get pregnant. Being nervous can delay it though.
Any length of time is a 'normal' time.