Stranger's baby.
No hesitation whatsoever.

Depends on whose odds were the better choice for saving

My mother. Imagine if this same situation happened when that schmuck Hitler was born, or Mao, or Stalin?

My mother is dead. Who is the 'stranger'?

If I had saved my Mother*, she would have murdered me for not saving the baby.

-* She died about 4 years back.

I find the comments below insightful; if you notice, a few people talk about saving the mom b/c family ties obviously, but the other most common reason is the baby could grow up and be another Hitler, Stalin, Mao, etc. Those that save the baby either do it b/c that's what their mom would want, their mom is a POS, or the baby has the probability of a longer life ahead. What if the baby grew up and became another Ghandi, MLK, Galileo, Einstein, Helen Keller, Mandela, Churchill, Socrates, Amelia Earhart, Lincoln, Frederick Douglass. These people were human, and had faults of course, but I think we all agree they raised our collective consciousness, intelligence, and/or empathy toward others. I find it curious that we seem to default to a jaded - glass half empty mentality when evaluating the value of a person.

Just an observation....

This is a moral dilemma....! My mother is dead a long time now, but in any case I know this is all only a hypothesis. My answer would be dependent on the age of my mother at the time. If she was an old lady, I would definitely choose the baby. If she was a younger woman, I would probably choose my mother.

My mother has been gone a longtime. Hypothetically, if she were alive, I would choose my mother. The vast majority of children grow up to be adults I don't really like. I already like my mother.

How about killing the bastard threatening the baby and the pensioner

Cute but basic. It all depends on how much you let yer heart rule yer head.

Baby

I would manage to save both.... (I can't do anything about your hypothetical question, as you can't do anything about mu hypothetical answer).