Can the growth hormone affect the penis size?

No but. During fetal growth there is an influence. After the post natal period, gh plays no significant role in penile length, only testosterone (endogenous) during the mini and full puberty. Injectable testosterone will enhance penis size during the first 6 months of life but has little effect latter on.
No. Hgh is only prescribed in children diagnosed with a true growth or height deficiency due to a pituitary gland disorder. Hgh has no effect on anatomic size or height in adults.

Related Questions

Does human growth hormone increase an adult's penis size?

No. Once you've reached adulthood growth is done. However, if you're an adult with gh deficiency, you may suffer from poor libido and maybe some depression. In this situation, replacing growth hormone may help to restore libido and improve mood. Read more...