The most common and most likely answer to this crossword clue is the 6 letter word UTERUS
I've seen this crossword clue in The Guardian
U
T
E
R
U
S
More clues leading to the result UTERUS
- Some fissure turned up as a source of life
- Here Labour begins true representation in America
- States true version up front: ‘It was one’s first abode’
- Organ certain to turn up under urologist’s coat
- Not entirely destitute, Russian in a warm, comforting place
- Source of issue among computer users
- Certain trade union backtracked to provide development area
- Human development centre?
- First human settlement in America — maybe true
Buddy explains!

The straight part
We know that "Source of issue" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case source of issue = uterus.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does UTERUS mean?
UTERUS noun- The womb, an organ of the female reproductive system in which the young are conceived and develop until birth.