Although individuals with Swyer syndrome develop a vagina, uterus, and the corresponding external genitalia, they do not develop the associated sex glands, known as the ovaries. Instead, they have what is known as streak gonads, in which the incomplete development of the ovaries leads to replacement by functionless connective tissue that does not secrete sex hormones. Due to the lack of ovaries, individuals with Swyer syndrome are infertile and cannot naturally conceive. However, with help of donated eggs, individuals with Swyer syndrome can still carry a baby to term.  In addition, younger individuals with Swyer syndrome typically do not undergo puberty because the lack of ovaries results in an inability to produce sex hormones, such as estrogen and progesterone, which are required for puberty. However, in cases of early diagnosis, often directed by signs of delayed puberty, such as the absence of menstrual cycles by the age of 14 (i.e. primary amenorrhea), individuals with Swyer syndrome can be treated with hormone therapy and eventually undergo puberty. Swyer syndrome also increases the risk of developing gonadal tumors in late adulthood, which can progress to invasive carcinomas of the streak gonads. If left untreated, tumors of the gonads can affect the reproductive system by increasing in size or by spreading cancerous cells to other abdominal organs.