I have 3 kids the youngest is 13 We want another...

What treatments are available for inability to conceive a baby?
Treatment of the cause according to the results of the tests
Take semen boosters and multivitamines for men
Determination of menstrual ovulation in women and have intercourse at this time to increase the likelihood of pregnancy
injection of sperm within the womb through a simple procedure under medical supervision
artificial fertilization of  ovum with an sperm and re-implantation of the fertilized egg inside the woman's womb. This is a last resort if the previous methods fail
What are the necessary tests in your case  ?
Blood test for both spouses
Clinical examination of both
ultrasound Image of both genitals
Hormone screening
Analysis of semen of man
What are the causes of inability to conceive a baby?
Urinary tract infection (urethra, ureter, prostate, bladder and kidney)
Varicose veins of the man
Problems with the glands
Immune problems
Weak ovulation in women
Lack of ovulation in women
aging of the ovaries
Polycystic ovaries for women
Severe inflammation of the uterus or cervix or ovary