2.1 Study area
The study was conducted at Agaro town, Jimma Zone, Southwest Ethiopia. It is located 45km from Jimma town and 391km from Addis Ababa. There are educational services from kindergarten to university in the town and it has two health centers and one primary hospital. There are 2 secondary and preparatory schools and 4 secondary schools in the town. According to the data obtained from school directors, the school had 2818 total regular secondary and preparatory students during the study period.
2.2 Study period
The study was conducted from April 13 to April 20, 2019.
2.3 Study Design
A descriptive facility based cross-sectional study was conducted among secondary and preparatory school students at Agaro town.
2.4 Study population
The source population comprised of all Agaro secondary and preparatory school students during the academic year of 2019, while the study population comprised all Agaro secondary and preparatory school students who fulfilled the inclusion criteria.
Eligibility criteria
Regular students were included in the study, whereas students absent from class on data collection days, sick and married students were excluded.
2.5 Sample size determination
The sample size was determined using single population proportion formula considering the following assumptions: P = 28.9% (26), significance level 5% and margin of error 5%.

Where n= required sample size
Z = Percentiles of the standard normal distribution corresponding to 95 % confidence level assumption
Coefficient at level of significance = 1.96
p =28.9% proportion of parent young communication (according to study done in Mizan)
d = Margin of error=0.05
Accordingly it gives initial sample size of 317. Since the source population is less than 10,000, (2818), we employed population correction formula for a finite population.

Where:
n = sample size
N = total population (2818)
nf=final sample size
By taking into consideration 10% non-response rate, the final sample size was 286+28.6= 315.
2.6 Sampling procedure
Stratified random sampling technique was employed to select study participants. First the sampling frame was prepared by having lists of students from grade 9 to 12 and then the sample population was proportionally assigned to each grade. Proportional allocation was done by allocating sampling proportional to the total population of each unit, using the formula:

Where ni =sample size of students from each grade, n=total sample size of students, N=total population of students, and Ni = total population of students at each grade. Finally samples were selected from each class by simple random sampling technique using students’ roster (Figure1).
2.7 Operational definition
Parents: in this study mean biological parents, step parents or foster parents but does not include elder siblings(27).
Parent-young communication on SRH: Students open discussion on at least two SRH issues (STIs/ HIV/AIDS, condom, sexual intercourse, premarital sex, puberty, menstrual cycle, unwanted pregnancy and contraception) with their parents in the last 12 months initiated by the young population or both(28).
Secondary school students: students who were in grade 9 and 10.
Preparatory school students: students who were in grade 11 and 12.
Regular students: students who were assigned on working day (from Monday to Friday) on regular working hour.
Young people: In this study context are peoples who are between 10–24 year olds.
Ever got SRH information = in this study context participants who had SRH information on at least two SRH issues during their life time.
Residence: In our study context place where students live for at least six months.
Ethnicity: nation of the study participant they belongs.
2.8 Data collection instrument
Data were collected using pretested, validated, self-administered structured questionnaire which was developed through reviewing different related scientific literatures(6,25,26,29) and it was pre-tested before collecting data to ensure data quality. The data were collected by six diploma graduate nurses under the supervision of two supervisors and principal investigator. Data collectors were supervised by two diploma midwives.
2.9 Data quality control
Data quality was ensured through standardized data collection materials and the English version questionnaire was translated to local language (Oromic) version for appropriateness and easiness by language experts in both cases. The Oromic version was again translated back to English language to verify the content validity of the original version.
Two days of training was given for data collectors about the aim of the study, how to approach the study subjects, sampling procedure and the content of the questionnaire. The questionnaires were pre-tested on 5% of participants at the Jiren secondary and preparatory school one week ahead of actual data collection and further modified based on the results. Continuous follow-up and supervision were made by the two supervisors and principal investigator and collected data were reviewed and checked daily for clarity, completeness and consistency.
2.10 Data entry, processing and analysis
The collected data was compiled, reviewed, coded and entered in to Epidata version 3.1 and exported to SPSS version 20 for analysis. Data was checked and cleaned for its completeness and errors in coding and entering before analysis. Descriptive statistical analysis was used to compute frequency and a percentage of independent and dependent variables. A logistic regression model was computed to see the association of independent variables and dependent variables. Variables with 𝑝 ≤ 0.25 on bivariable logistic regression were considered as candidates for multivariable regression and P-values of < 0.05 were considered to be statistically significant in the multivariable analysis. Crude and adjusted odds ratios with their 95% confidence intervals were calculated. The Hosmer and Lemeshow goodness-of-fit test were checked and gave a p value of 0.704, indicating evidence of fitness of the model. The variance inflation factor was used to verify the multico-llinearity between the independent variables, and no findings were found.