Congratulations! You found your ancestor in the 1880 census, a 14-year-old boy living with his parents and several siblings, both older and younger! You gleefully place these new names on your family chart and proceed on with your research. Right?
No, of course not! You realize that this young man may well be the son of the head of the household (he's listed as the man's son, after all), but that woman might be his mother, or may be someone his widowed (or divorced) father may have married after the boy's mother died.
Since you've already tried getting a full death record to see if his parents are listed (no, the space is blank), and his obituary (not mentioned), you know you have to try another few tricks. You look for will and/or probate records, but, although the father's will mentioned his children by name, the woman died before her husband.
You look for marriage records and find a record for the father marrying a woman of the correct first name a year before the oldest child in the family was born. But as you check further and discover the father married again, in 1872, to a woman with the same first name as his first wife. You find a cemetery listing for the first wife (you ignored it before, thinking she was still alive in 1880), and all of the pieces are falling into place. A close examination of church records verifies your theory: Your ancestor was the son of the 1880 head of household and his first wife. And you have successfully resisted the urge to jump to a conclusion without all of the facts.
NOW you can add those names in the proper places!