Question: Which gender has more bone marrow stem cells during reproductive years?
About the article "Stem cell", section "Adult".

Candidate passages:
Adult stem cells, also called somatic (from Greek Σωματικóς, "of the body") stem cells, are stem cells which maintain and repair the tissue in which they are found.
They can be found in children, as well as adults.
Pluripotent adult stem cells are rare and generally small in number, but they can be found in umbilical cord blood and other tissues.
Bone marrow is a rich source of adult stem cells, which have been used in treating several conditions including spinal cord injury, liver cirrhosis, chronic limb ischemia and endstage heart failure.
The quantity of bone marrow stem cells declines with age and is greater in males than females during reproductive years.
Much adult stem cell research to date has aimed to characterize their potency and self-renewal capabilities.
In mice, pluripotent stem cells are directly generated from adult fibroblast cultures.
However, mice do not live long with stem cell organs.
Most adult stem cells are lineage-restricted (multipotent) and are generally referred to by their tissue origin (mesenchymal stem cell, adipose-derived stem cell, endothelial stem cell, dental pulp stem cell, etc.
Adult stem cell treatments have been successfully used for many years to treat leukemia and related bone/blood cancers through bone marrow transplants.
Adult stem cells are also used in veterinary medicine to treat tendon and ligament injuries in horses.
The use of adult stem cells in research and therapy is not as controversial as the use of embryonic stem cells, because the production of adult stem cells does not require the destruction of an embryo.
Additionally, in instances where adult stem cells are obtained from the intended recipient (an autograft), the risk of rejection is essentially non-existent.
Consequently, more US government funding is being provided for adult stem cell research.
For over 30 years, bone-marrow, and more recently, umbilical-cord blood stem cells, have been used to treat cancer patients with conditions such as leukaemia and lymphoma.
During chemotherapy, most growing cells are killed by the cytotoxic agents.
These agents, however, cannot discriminate between the leukaemia or neoplastic cells, and the hematopoietic stem cells within the bone marrow.
It is this side effect of conventional chemotherapy strategies that the stem cell transplant attempts to reverse; a donor's healthy bone marrow reintroduces functional stem cells to replace the cells lost in the host's body during treatment. 
Vertebrate Adult stem cell niches.A.
Hematopoietic stem cell niche.
Vertebrate hematopoietic stem cells niche in the bone marrow is formed by cells subendosteal osteoblasts, sinusoidal endothelial cells and bone marrow stromal (also sometimes called reticular) cells which includes a mix of fibroblastoid, monocytic and adipocytic cells. 
Adult stem cell treatments have been used for many years to successfully treat leukemia and related bone/blood cancers utilizing bone marrow transplants.
The use of adult stem cells in research and therapy is not considered as controversial as the use of embryonic stem cells, because the production of adult stem cells does not require the destruction of an embryo.
Early regenerative applications of adult stem cells has focused on intravenous delivery of blood progenitors known as Hematopetic Stem Cells (HSC's).
CD34+ hematopoietic Stem Cells have been clinically applied to treat various diseases including spinal cord injury, liver cirrhosis and Peripheral Vascular disease.
Research has shown that CD34+ hematopoietic Stem Cells are relatively more numerous in men than in women of reproductive age group among spinal cord Injury victims.
Other early commercial applications have focused on Mesenchymal Stem Cells (MSCs).
For both cell lines, direct injection or placement of cells into a site in need of repair may be the preferred method of treatment, as vascular delivery suffers from a "pulmonary first pass effect" where intravenous injected cells are sequestered in the lungs.
Clinical case reports in orthopedic applications have been published.
Wakitani has published a small case series of nine defects in five knees involving surgical transplantation of mesenchymal stem cells with coverage of the treated chondral defects.
Centeno et al.
have reported high field MRI evidence of increased cartilage and meniscus volume in individual human clinical subjects as well as a large n=227 safety study.
Many other stem cell based treatments are operating outside the US, with much controversy being reported regarding these treatments as some feel more regulation is needed as clinics tend to exaggerate claims of success and minimize or omit risks. 
Cortical bone is well vascularized by the surrounding soft tissues thus less susceptible to ischaemic damage.
Cancellous bone, with its mesh like structure and spaces filled with marrow tissue is more susceptible to damage by bone infarcts, leading to Hypoxia (medical) and premature cell apoptosis.
The mean life-span of osteocytes has been estimated to be 15 years in cancellous bone, and 25 years in cortical bone.
while the average lifespan of human osteoclasts is about 2 to 6 weeks and the average lifespan of osteoblasts is approximately 3 months.
In healthy bone these cells are constantly replaced by differentiation of bone marrow mesenchymal stem cells (MSC).
However, in both non-traumatic osteonecrosis and alcohol-induced osteonecrosis of the femoral head, a decrease in the differentiation ability of mesenchymal stem into bone cells has been demonstrated, and altered osteoblastic function plays a role in ON of the femoral head.
If these results are extrapolated to ONJ the altered differentiation potential of bone marrow mesenchymal stem cells (MSC) combined with the altered osteoblastic activity and premature death of existing bone cells would explain the failed attempts at repair seen in ischaemic-damaged cancellous bone tissue in ONJ.
The rapidity with which premature cell death can occur depends on the cell type and the degree and duration of the anoxia.
haematopoietic cells, in bone marrow, are sensitive to anoxia and are the first to die after reduction or removal of the blood supply.
In anoxic conditions they usually die within 12 hours.
Experimental evidence suggests that bone cells composed of osteocytes, osteoclasts, and osteoblasts die within 12–48 hours, and marrow fat cells die within 120 hours.
The death of bone does not alter its radiographic opacity nor its mineral density.
Necrotic bone does not undergo resorption; therefore, it appears relatively more opaque.
Attempts at repair of ischaemic-damaged bone will usual occur in 2 phases.
First, when dead bone abuts live marrow, capillaries and undifferentiated mesenchymal cells grow into the dead marrow spaces, while macrophages degrade dead cellular and fat debris.
Second, mesenchymal cells differentiate into osteoblasts or fibroblasts.
Under favorable conditions, layers of new bone form on the surface of dead spongy trabeculae.
If sufficiently thickened, these layers may decrease the radiodensity of the bone; therefore, the first radiographic evidence of previous osteonecrosis may be patchy sclerosis resulting from repair.
Under unfavorable conditions repeated attempts at repair in ischaemic conditions can be seen histologically and are characterized by extensive delamination or microcracking along cement lines as well as the formation of excessive cement lines.
Ultimate failure of repair mechanisms due to persistent and repeated ischaemic events is manifested as trabecular fractures that occur in the dead bone under functional load.
Later followed by cracks and fissures leading to structural collapse of the area involved (osteocavitation).