Now this is only one example of an odd little ligament - but I was totally surprised to discover that the connective tissue actually changed over time...and that some of the changes happened between the first and second decade and the second and
third of life. This really helps make the case for avoiding hard conditioning in youth since you can't know where they fall on the developmental scale. And it also speaks to how the body is continually adapting to the stesses placed on it either through developmental changes or activities. There is no reference in the abstract to gender difference but perhaps in the actual article. This also recalls to mind something I've heard before in that you can't really peak in your iron shirt training until you're in your late 30's to early 40's.
This is the anatomical structure:
This is the medical-speak about it from PubMed.
J Bone Joint Surg Br. 1986 Mar;68(2):197-200.
The iliolumbar ligament. A study of its anatomy, development and clinical significance.
by
Luk KD, Ho HC, Leong JC.
The development of the iliolumbar ligament and its anatomy and histology were studied in cadavers from the newborn to the ninth decade. The structure was entirely muscular in the newborn and became ligamentous only from the second decade, being formed by metaplasia from fibres of the quadratus lumborum muscle. By the third decade, the definitive ligament was well formed; degenerative changes were noted in older specimens. The iliolumbar ligament may have an important role in maintaining lumbosacral stability in patients with lumbar disc degeneration, degenerative spondylolisthesis and pelvic obliquity secondary to neuromuscular scoliosis.