Too many variables to give just a standard answer. A lot depends on both parties involved, the nature of the relationship, and what she ultimately intends to do.

Depends on the guy and the circumstances of the conception. @witchymom covered the circumstances part well. As long as the guys not a total dick and has half an emotional clue I think it would be best to tell him. Whether she carries the child to term or aborts is ultimately up to her tho. 'Her body, her rules' trumps all.

I don't have to worry about that. Ive had vasectomy

Too simple of a question. Different circumstances would produce a different answer.
One example. A woman get pregnant by an abuser. She finally gets away from him and then discovers than she is pregnant. Due to all the abuse and trauma and personal beliefs, she does not terminate the pregnancy. The father is very abusive and the woman fears for her life and the life of the child. She gives birth to the child and raises the child by herself and never tells the abuser that he has fathered a child. Or if he knew that she was pregnant she told him that she had a miscarriage.
Does anyone thinks that she made the wrong choice and the father deserves to know about the child.
Second example. A woman was fooling around with this guy on the rebound. She then found out that she is pregnant but tell the old boyfriend or husband that the baby is his when she knows that the father is the rebound lover. The rebound lover is actually a good guy who would step up and be a great father to the child and a great husband or boyfriend to the woman. The woman has the child and passes the child off as the offspring of the man she wants to be with.
Does anyone thinks that she made the wrong choice and the father deserves to know about the child.
No right answer, and this is just two scenarios that actually happened to two people that I know.

I think a man has the right to know if the woman decides to carry it to term. I'm a dad, and would be devistated to learn that I have other children who don't even know me.

I'm considering going through a sperm bank, so the point is moot for me.

But in previous relationships and hookups, there is only one person I would not have told if he had gotten me pregnant. The rest I would have alerted. Even if I didn't plan to keep the pregnancy, abortion isn't cheap and I could use help in paying for one. They contributed 50% of the genetics required to make a blastocyst, they can contribute 50% of the funds to keep it from continuing to leech off me. >.> But if I did decide to keep the pregnancy, they should be aware of their genes being spread and provide their medical information. I've always been of the mind that if they don't want to provide child support or be an involved father, then they need to legally sign away all their rights to the child.

First of all, this is a situation which no grown ass man will ever put a woman in to. A grown ass man will take the responsibility to wear a condom.

If it gets to the point where a woman has to make that phone call, then the dude has already proven that he lacks the maturity to be involved in raising a child. So no, a woman has no obligation to contact him or inform him regarding any decisions requiring an adult.

And she should probably take a good, honest look at the quality of men she's giving the most intimate parts of herself to.

It would be respectful, but it's not required.

depends on the relationship

It depends on the situation.

I'd say yes... having grown up without knowing my father and recently finding out my mom kept me from him because she worried he'd take me from her & give me a better life. It really bugged me finding out that my mom was selfish in that aspect.... Very few circumstances are valid to not say anything. If it was someone abusive, neglectful, or the father would be a deadbeat in some way, I'd understand. Consider that when a child grows into adulthood they may want to find their other biological parent, and may also be a bit fruatrated/resentful if you kept them from their other parent.

It's a bit academic to me now -I'm 58 and had a vasectomy many years ago but i think my answer would be a subjective 'yes'
There should be responsibilies that comes ( excuse the pun )with sexual activities and imo those responsibilities should apply to men and women

Can’t really answer this one. I ain’t never been knocked up. Hate the word pregnant.

If the guy did not care enough to either prevent the pregnancy or hang around long enough to have been part of the finding out about being pregnant then no, he's already shown that he does not care. I would not be telling him under those circumstances.

That said, it's a moot point. I did not have unattached casual sex (or unprotected sex) during my reproductive years. Now, the risk of conception is past for me.

There are to many situations to determine the answer to this question .Different situations require different answers

Been there, was a father and a grandfather on the same day, I found out about my daughter, conceived the night before I left for the army, the day my grandson was born she decided to tell me I was a father. It doesn't matter who squirts it only matters who does the parenting, make sure that's what drives your decision, give your baby an education.

I agree with @witchymom on this. For me personally, I don't need to know. I'd be shocked if it ever comes up as I had a vasectomy more than 20 years ago.

Unless there was violence involved I would say yes - informing if for no other reason than getting some genetic background on the father. In reality there is also financial obligation on the part of the father. - Was dating a jerk - for 2 years - he moved out of his apartment and relocated (I had no knowledge of this) 1 week before I tested positive. Lost the baby at 5 months and still question if this very immature person was ever going to be of any use to myself or my child? But I still believe it was the right thing to do.

I a man think that decsision is up to you

There are many missing facts regarding this question. ...is this couple planning a family ? Has the agreed upon birth control method failed or been abandoned ? Is the woman healthy enough to stay pregnant ? Has an ultrasound ruled out ectopic pregnancy ? Is the questioner trying to smoke out boys who won't support her decisions emotionally financially legally socially medically ?????

It all depends on what relationship you are with him. If a fling or a one night stand, I don't think the man will be interested to know. But if both are committed to the relationship then of course the guy will like to know.

The guy absolutely has the right to know.

A mute point withe us guys. A woman can choose to keep the child or not. Now as much as I support the women's right to do so, with the exception of rape I think the father should be informed. As it stands if a woman wants the child, the guy is on the hook for up to 21 years. Irrespective of the circumstances. Whether they be statutory rape (on her part), or if she loads up a turkey baster from her mouth/condom. It makes no odds. Similarly if she terminates he has no say. He could be the last of the mohicans or heir to some Scottish clan.
There may be other circumstances that might inform her decision too. Like genetic disorders or he could have a very low sperm count and this might be his only chance of kids.
It takes two to tango. Two should know.

Personally, I'm like the other guys here who it wouldn't affect, I had a vasectomy in 1974, I couldn't wait to get home and try it out. But otherwise there are just too any variables involved. However, if the woman wants to abort the pregnancy I think that would be her decision. It would be between her and her doctor. She would have the right to do as she chooses with her own body and should be no one elses business.

You have opened a can of worms, and my rant....
Though a woman is burdened with the pregnancy biology is not her fault nor his. They are both equilly responsabie for the pregnancy. If there is a question as to wether the pregnancy should be terminated the default should be baby,excluding rape etc.
I once had a woman suggest I was the father of her child. This was as soon as she got married and the new husband wanted to get PAID. I was pissed. My atterney was shocked when I suggested that she owed me compensation for depriving me of being a father and I wanted sole custody of the 14 y/o child so that I could be a father of the child for his remaining childhood years as she had intentionally deprived me of being a father.

He was not my child and it was not an issue. My wife and I have two children. A very progressive outlook is that parents share 50/50 the child raising duties right? Bullcrap. We have never seen it that way. We both give 100%. so the children get 200% of our combined efferts. There was never any question as to who changed diapers or anything else. It always came down to whom was the best to attend to the needs at the time. If I was busy she did it and vis a versa.

I know I may be an exception. But it is both of our creation and responseability. Every man should be completely involved unless he is a complete loser.