There are a lot of high level evidence available  - Dutasteride and Finasteride works similar - and with long term experience: Dutasteride and Finasteride are not recommended in patientes with the wish to become a baby

Samplaski et al 

Finasteride use in the male infertility

population: effects on semen and

hormone parameters

Fertility and Sterility® Vol. 100, No. 6, December 2013 0015-0282/$36.00

Copyright ©2013 American Society for Reproductive Medicine, Published by Elsevier Inc.

http://dx.doi.org/10.1016/j.fertnstert.2013.07.2000ry

Apart from drug side effect, male fertility potential decrease with aging

http://www.omicsgroup.org/journals/evaluation-of-age-effects-on-semen-parameters-of-infertile-males-2167-0250.1000106.php?aid=15491

Unfortunately, there ist not in all cases reversible after discontinuation, its depend also from time duration of taking 5 ARI - called "Post finasteride-syndrome

J Clin Psychiatry. 2012 Sep;73(9):1220-3. doi: 10.4088/JCP.12m07887. Epub 2012 Aug 7.

Depressive symptoms and suicidal thoughts among former users of finasteride with persistent sexual side effects.

Irwig MS1.

Author information

Abstract

OBJECTIVE:

Finasteride, a commonly prescribed medication for male pattern hair loss, has recently been associated with persistent sexual side effects. In addition, depression has recently been added to the product labeling of Propecia (finasteride 1 mg). Finasteride reduces the levels of several neuroactive steroids linked to sexual function and depression. This study assesses depressive symptoms and suicidal thoughts in former users of finasteride who developed persistent sexual side effects despite the discontinuation of finasteride.

METHOD:

In 2010-2011, former users of finasteride (n = 61) with persistent sexual side effects for ≥ 3 months were administered standardized interviews that gathered demographic information, medical and psychiatric histories, and information on medication use, sexual function, and alcohol consumption. All former users were otherwise healthy men with no baseline sexual dysfunction, chronic medical conditions, current or past psychiatric conditions, or use of oral prescription medications before or during finasteride use. A control group of men (n = 29), recruited from the community, had male pattern hair loss but had never used finasteride and denied any history of psychiatric conditions or use of psychiatric medications. The primary outcomes were the prevalence of depressive symptoms and the prevalence of suicidal thoughts as determined by the Beck depression inventory II (BDI-II); all subjects self-administered this questionnaire at the time of the interview or up to 10 months later.

RESULTS:

Rates of depressive symptoms (BDI-II score ≥ 14) were significantly higher in the former finasteride users (75%; 46/61) as compared to the controls (10%; 3/29) (P < .0001). Moderate or severe depressive symptoms (BDI-II score ≥ 20) were present in 64% (39/61) of the finasteride group and 0% of the controls. Suicidal thoughts were present in 44% (27/61) of the former finasteride users and in 3% (1/29) of the controls (P < .0001).

CONCLUSIONS:

Clinicians and potential users of finasteride should be aware of the potential risk of depressive symptoms and suicidal thoughts. The preliminary findings of this study warrant further research with controlled studies.

Persistent Sexual Side Effects of Finasteride: Could They

Be Permanent?jsm_2846 1..6

Michael S. Irwig, MD

Center for Andrology and Division of Endocrinology, The George Washington University, Washington, DC, USA

DOI: 10.1111/j.1743-6109.2012.02846.x

A B S T R A C T

Introduction. Finasteride has been associated with sexual side effects that may persist despite discontinuation of the

medication. In a clinical series, 20% of subjects with male pattern hair loss reported persistent sexual dysfunction for

6 years, suggesting the possibility that the dysfunction may be permanent. These subjects also reported a wide

range of symptoms including changes in cognition, ejaculate quality, and genital sensation. Other medications have

been associated with irreversible neurological effects, such as phenothiazines with tardive dyskinesias.

Aim. To prospectively study whether the persistent sexual side effects associated with finasteride resolve or endure

over time.

Methods. Subjects (N = 54) with persistent sexual side effects associated with finasteride were reassessed after 9–16

months (mean 14 months). All subjects were otherwise healthy young men without any baseline sexual dysfunction,

medical conditions, psychiatric conditions, or use of oral prescription medications prior to taking finasteride for male

pattern hair loss.

Main Outcome Measure. Scores from the Arizona Sexual Experience Scale (ASEX).

Results. The participation rate was 81%. At reassessment persistent sexual side effects continued to be present in

96% of subjects. According to the ASEX scores, 89% of subjects met the definition of sexual dysfunction. Neither

the length of finasteride use nor the duration of the sexual side effects correlated to changes in scores of sexual

dysfunction.

Conclusion. In most men who developed persistent sexual side effects (3 months) despite the discontinuation of

finasteride, the sexual dysfunction continued for many months or years. Although several rat studies have shown

detrimental changes to erectile function caused by 5 alpha reductase inhibitors, the persistent nature of these changes

is an area of active research. Prescribers of finasteride and men contemplating its use should be made aware of the

potential adverse medication effects. Irwig MS. Persistent sexual side effects of finasteride: Could they be

permanent? J Sex Med **;**:**–**.