I have read about this somewhere where it said that a child could resemble someone who sleeps with a pregnant woman but is not the father of that soon-to-be-born baby. Is that true?
From genetics’ point of view, no, that is not possible. All genetic material for human being comes from the two parents, except for a few exceptions in some cases of test-tube fertilization. Basically, nothing the woman has done during or after the pregnancy will change the look of the child. However, it is possible for a baby to resemble anyone in the world, and it’s not impossible that the person a baby resembles had sex with the mother at one given time.
I’ve read on Wikipedia about Telegony, a theory in heredity, holding that offspring can inherit the characteristics of a previous mate of the female parent; thus the child of a remarried woman might partake of traits of a previous husband. This theory has been proven wrong many times but it’s constantly being brought up as an argument.