The male’s reproductive role is to produce sperm and deliver to the vagina. These functions require four different structures. These are the:
Testes
Accessory glands
Accessory ducts
Penis

The functions of the male reproductive system are:
1. Production of sperms.
2. Transmission of sperms to the female.

How does it work ?

After the process of sexual intercourse, the sperm makes its way through the vagina into the fallopian tubes. The quality and quantity of the mucus depends on the levels of  two  principle sex hormones : estrogen and progesterone.
The sperm then reaches the egg. It is very difficult for sperm to reach the fallopian tubes when estrogen levels are low because the mucus becomes thick and sparse.
But when estrogen levels are high, the mucus is thin and slippery and the egg is ready for fertilization. This is a much better environment for sperm.

Hormones and the male reproductive system: Sperm production

In males, the testes produce male sex hormones called androgens (from the Greek word andros, meaning "man"). Testosterone is the most important of these. It spurs the growth of the male reproductive organs and the production of sperm.

Also, Testosterone brings about the male secondary sex characteristics: deepening of the voice; appearance of hair under the arms, on the face, and in the genital area; and increased growth of muscles and heavy bones.

Testosterone is produced in the male fetus to stimulate the formation of the male duct system and accessory organs. I

Millions of sperms are formed each day in the testes. Although this number decreases as a man ages, the production of sperm never completely stops.  There are numerous diseases that  are related to this system.  You may check them on : Male Reproductive Problems .

Male Sexual Energy
As per Traditional  Indian Health Care System~ Ayurveda,  male sexual energy emerges from the male reproductive tissue. 
It is this tissue which provides you potential energy for reproduction.   It also acts as a  fuel for mental focus, concentration, clarity and  creativity.

Most of us are unaware of the fact that high amounts of toxins in the body are also one of the obstacles in the reproductive health.  

Causes  of  reproductive problems ( especially low sexual energy ) :
Poor diet and inappropriate food; tobacco, alcohol, marijuana
Emotional strain
Over indulgence in sex
Old Age
Genetic
Pharmaceutical drugs.
Stress
Overwork
Chronic Prostate  infection prostate
Endocrine disorders
Excessive use of astrigent, salty,spicy and sour foods.
Wearing tight underwear and pants.
Prolonged use of bitter herbs like Neem may affect your libido and sperm count.

Be responsible for your Reproductive System
Now, as you  have become aware of the it factors that are contributing to the malfunctioning or imbalance of the repsoductive system,  Your primary concern should be to eliminate the factors, be it emotional, dietary, mental or otherwise.

Practice Proper Hygiene
Keep your genitals clean at all  the times. Wash them regularly with soap and water, especially after using the toilet. This way, you can prevent any infections caused by dirt and germs accumulating in your sex organs. Also, make sure to wear only clean underwear and change them as often as necessary

Don't ignore your prostate. It's important to get tested for prostate cancer as recommended by your doctor. This disease may not show symptoms in its early stages, when it is easier to treat. This is the most common cancer in men, but is usually not fatal if treated in time.

Take care of your testicles. Wear protective gear if you play sports. Even a minor injury to this area can cause severe pain. You should also perform regular testicle self-exams to protect against testicular cancer. If you notice anything unusual, tell your doctor.

Be aware of workplace hazards. Exposure to chemicals and radiation in the workplace can harm your reproductive health. These problems can range from cancer to infertility. Talk to your doctor and supervisor about ways to protect yourself.

Be Safe
If you’re sexually engaged with your partner, make sure to use protection when you have sex. Methods such as condoms are not just for reducing pregnancy risks; they also promote your sexual health. If you use the right protection, you’ll have less chance of contracting any STDs, or of passing the disease on to your partner

How do you take care of your reproductive organs? Here are some ways to do it:

1.    Clean your external sex organs every day. Wash them with soap and wash them after using the toilet.
2.    Change your underwear as often as necessary. What your underwear immediately after use.
3.    Keep your clean underwear in a clean place. Make sure they do not get any dirt or germs before you use them.

Herbs that work for you.

Ashwagandha

Being one of the best male rejuvenating tonic herbs, it promotes spermatogenesis, blood flow and tone to the reproductive organs and regulates hormonal function.  Best to be used as tincture.  The herb is hot in nature and can be used with cooling herbs  like   Shatavari and Liquorice.  When combined with Pippali, the combination increases blood flow to your reproductive organs.

Mucuna Pruriens
Very potent rasyana for the mind as well as for the reproductive organs and sexual energy. The herb is known to increase the sexual energy when prepared with other rejuvenating substances, like milk, ghee or honey

Korean Ginseng

This hearty root is considered to be one of the best male sexual tonics. support healthy libido, erectile dysfunction and enhance male sexual performance.

Gokharu

Tribulus is known to be very effective in improving sperm count, motility.  It is one of the best male reproductive system supporting herbs.

Maca
Herb is used to increase  libido, sperm count, motility of sperm, cures - decreased anxiety and stress, lowered blood pressure, balanced iron levels and an increase in adrenal androgens.

Shatavari
Acts as a powerful male tonic.  It is a cooling herb.  Beneficial for both men and female reproductive system.

Bala
Nourishes and strenngthens the reproductive tissues. The herb is known to promote sexual vigour and strengthe and stamina.

Saw palmetto
Saw Palmetto is nourishing to the entire endocrine system, which may help improve overall reproductive function in men.

Yohimbe
Supports healthy circulation to the male reproductive organs.  Known to sustain erection.
May help to make erection firmer.

Dear Men
The Herbs mentioned above and the lifestyle changes  stated above will make sure to guard your reproductive system and uproot the disorders, if any. 
So, take  Herbs, work on decreasing stress factors, and spare out some time to pause and rest, relax and play, give yourself some time, and ponder over how you feel deep inside and resolve the emotional issues.