How old should you have to be to...

[MODU]

Buy birth control?  18 (Because you shouldn't be having sex until...)
Have sex?  18
Get an abortion without parental involvement?  18 (For the same reason as question 1)
Drink alcohol?  21
Buy alcohol?  21 (Becuase you shouldn't be buying it until you are allowed to drink it)
Smoke cigarettes?  18
Buy cigarettes?  18 (Because you shouldn't be buying it until you are allowed to smoke it)
Watch a pornographic film?  18
Star in a pornographic film?  18 (For the same reason as question 1)
Drive?  16
Be able to drop out of school?  16
Rent your own apartment?  18 (Because you are not allowed to sign a contract until you turn 18)
Own your own business?  12 (but you cannot sign contracts without an "adult" as a cosigner until you turn 18)
Go to a strip club?  18
Fight a bull?  18 (Though why anyone would want to is beyond me)
Choose to go to a different place of worship than your parents?  No real age limit on this, though by age 18, you should be able to go wherever you want since you are no longer a dependent of your parents.

[MODU]

Buy birth control?  18 (Because you shouldn't be having sex until...)
Have sex?  18

Haha, so, MODU, the 'punishment' for breaking your law against sex is to have a baby?  Don't you think a good deal of that punishment falls upon the poverty stricken child?

Better to kill or castrate the offenders, no?

It's called being responsible for your actions.  If you break the law, you have to suffer the consequences of your actions.  Of course, that's an alien concept for you, right?

[MODU]

Buy birth control?  18 (Because you shouldn't be having sex until...)

I'm going to be a jerk and call you out on this a little.

By and large, it's probably dumb to have sex before 18.   I wouldn't say in every situation - I know very intelligent sexually active people under 18 who realize that there is a small chance of accidental pregnancy (very small), but are willing to take that risk.

But limiting birth control to 18+ is an horrible idea.  Do you really want the teenage pregnancy rate to skyrocket?  Teenagers don't have sex because condoms are available.  What are we going to do, prosecute people for handing out condoms to 17-year-olds?  Sorry, but that's ridiculous to me.

Remember, the topic is 'how old "should" you be' . . . which means the reasonable person "should" be obeying the rules.  Now if in a state where the right to consensual sex is 16, then the brith control purchase age should be . . . 16.  No teenagers "should" be having sex.  I didn't say my choices were realistic with the irresponsible youths that exist in society.