Dangerous to write to same pipe from 2 or more processes?

Title pretty much covers it.
I have a program with a variable number of childś writing to the same pipe, from witch the father reads.
Is this dangerous? can data be corrupted if execution jumps to another child, in the middle of the write, or is the write done in one cycle?

Thank You

http://www.minix3.org/manpages/man2/pipe.2.html
A single write() up to PIPE_MAX is atomic.

thank you