# Do all probabilities of an event HAVE to happen?

## Recommended Posts

So, this pertains to a somewhat personal issue, but I have been freaking out over the possibility of my girlfriend's birth control malfunctioning. I'm worried because, though it's said that BC is 99% effective, there is a 1% chance of pregnancy. So, is there a law of probability that says in the occurrence of a scenario, that the 1% possibility HAS/WILL to happen? I doubt I'd be the unlucky 1% over the course of a month..but think of the amount of intercourse over a 10 year period using BC. You're going to have to be that 1% eventually, right?

~EE

##### Share on other sites

I believe that percentage represents 1% of people consistently using birth control while being regularly 'active' for one year wind up getting pregnant anyway.

So even after ten years, you'd have a better than 90% chance of not getting pregnant (assuming I'm correct about what that number means).

That said, probabilities are probabilities. Even something with a 99% chance of happening does not have to happen, and even something with a 1% chance of happening may happen.

There's a real chance of getting pregnant from one encounter and a real chance of never getting pregnant ever while on birth control. The latter case is probably more likely than the former, but there are no 100%'s here.

##### Share on other sites

So, this pertains to a somewhat personal issue, but I have been freaking out over the possibility of my girlfriend's birth control malfunctioning. I'm worried because, though it's said that BC is 99% effective, there is a 1% chance of pregnancy. So, is there a law of probability that says in the occurrence of a scenario, that the 1% possibility HAS/WILL to happen? I doubt I'd be the unlucky 1% over the course of a month..but think of the amount of intercourse over a 10 year period using BC. You're going to have to be that 1% eventually, right?

~EE

No. There is no probability (other than 1) such that a result is mandated, or a probability that's not zero that makes something impossible.

##### Share on other sites

Why having a child is such freaking tragedy.. ? "Unlucky"?! I think it's great to have kids. Somebody would love to have kids but cannot.

##### Share on other sites

Why having a child is such freaking tragedy.. ? "Unlucky"?! I think it's great to have kids. Somebody would love to have kids but cannot.

I dont have the financial stability or time to raise a newborn.

##### Share on other sites

Just be careful Engineer as some medications can interfere with the pill such as Rifampin, Griseofulvin (antibiotics), and make make it less effective. Remember, it's 99% effective if taken correctly which means taking it at the same time each day.

Personally, I would recommend the copper IUD as a better method of contraception because once it's inserted, it lasts for 5 years and you don't have to worry about taking a pill at the same time of day everyday and it does relieve a lot of anxiety when traveling and away from home. It does not contain any hormones, unlike the pill it does not increase your chances of cardiovascular disease and breast cancer, it's more cost effective long term as you only have to pay for the IUD once and it lasts 5 years.

It's up to you and your girlfriend; the pill is just as effective as the Copper IUD if taken correctly. However, it depends on how much you trust your girlfriend to take it correctly.

If you want to be safer, you could just use a condom as well.

Why having a child is such freaking tragedy.. ? "Unlucky"?! I think it's great to have kids. Somebody would love to have kids but cannot.

You don't know how old he is, what his financial position is, what his personal philosophy on having children is (lots of people don't want to have children).

Edited by Sirona

##### Share on other sites

...

You don't know how old he is, what his financial position is, what his personal philosophy on having children is (lots of people don't want to have children).

Also, could be on medical therapy that advises against it or be genetically predisposed to having children that may get a debilitating or life-threatening condition. Having a child could threaten the life of the mother.

##### Share on other sites

I dont have the financial stability or time to raise a newborn.

So you are in the same situation as 3/4 or 4/5 of the entire population of the world.

Edited by Sensei

##### Share on other sites

So you are in the same situation as 3/4 or 4/5 of the entire population of the world.

Stop pushing your personal agenda and save your judgements. These days (thankfully) having children is a choice (for most) and should involve careful consideration. Why turn it into an ethical debate? He's unsure of the effectiveness of the pill and not of the ethics of taking contraception.

##### Share on other sites

Or you could, you know, lessen the risk of pregnancy by reducing the activity. You know, cause... effect...

##### Share on other sites

Or you could, you know, lessen the risk of pregnancy by reducing the activity. You know, cause... effect...

Say one went from daily sex to twice or thrice weekly sex, one could actually be increasing the probability of pregnancy occurring because the sperm count and quality would be higher... concentration and population matters, particularly those men with lower counts and/or lower quality sperm.

##### Share on other sites

Swansont

No. There is no probability (other than 1) such that a result is mandated, or a probability that's not zero that makes something impossible

Sticking to the statistical part of this question,

How do you assign probabilities to something that has never happened?

##### Share on other sites

So you are in the same situation as 3/4 or 4/5 of the entire population of the world.

It's not even that..it's the fact that I want to live the life I want for myself...I just finished school and want to LIVE..not change diapers and get up at 4:30 am every morning to feed a crying baby.

Sticking to the statistical part of this question,

How do you assign probabilities to something that has never happened?

I thought this was the point of assessing probability is "risky" situations. You take a scenario, run the probability of the potential risk, and make a decision.

Say one went from daily sex to twice or thrice weekly sex, one could actually be increasing the probability of pregnancy occurring because the sperm count and quality would be higher... concentration and population matters, particularly those men with lower counts and/or lower quality sperm.

So, regardless, more sex = increase in probability even with 99% effectiveness...I guess this makes sense.

##### Share on other sites

So, regardless, more sex = increase in probability even with 99% effectiveness...I guess this makes sense.

Counterintuitively, I was suggesting less sex = increase in probability.

##### Share on other sites

I thought this was the point of assessing probability is "risky" situations. You take a scenario, run the probability of the potential risk, and make a decision

And how exactly do you 'run the probability' (ie what probability do you use) if the event has never happened?

BTW this is a serious issue in statistics that has been argued for several centuries and is not yet properly resolved.

'Classical' statistics has no answer, you need to go to Bayes theorem.

##### Share on other sites

And how exactly do you 'run the probability' (ie what probability do you use) if the event has never happened?

BTW this is a serious issue in statistics that has been argued for several centuries and is not yet properly resolved.

'Classical' statistics has no answer, you need to go to Bayes theorem.

Darn..further down the rabbit hole. So if people had sex, will there be one instance of pregnancy..or is this too limited by classical stats?

##### Share on other sites
And how exactly do you 'run the probability' (ie what probability do you use) if the event has never happened?

In this case, the event - pregnancy and nonpregnancy while taking birth control pills - has happened, many times, in the relevant population.

As long as I'm idly shooting off my mouth:

I have a few sisters, and a girlfriend or two in my history, and this from that: I'd worry more about the psychological aspect of birth control pills than the probably nonexistent breast cancer and cardiovascular disease risk (especially given the lower risk of other stuff, such as ovarian cancer and, y'know, pregnancy). They're hormones: they affect mood and response, and in this case they affect stuff directly involved in romantic pair bonding.

Also: Studies, as well as experience, show that the immediate prospect of parenthood, including companionship with a beloved and pregnant woman, alters the man's hormones as well: you will find yourself in a much different state of mind than you now project, if the feared disaster of pregnancy befalls you. Take care of business, and then don't worry about it - unless what you actually fear is the prospect of being stuck with this woman for years, in which case you guys need to talk.

Just my opinion. YMMV.

Edited by overtone

##### Share on other sites

So you are in the same situation as 3/4 or 4/5 of the entire population of the world.

And smarter than most of them because he's knows he's not ready for a kid.

## Create an account

Register a new account

×

• #### Activity

×
• Create New...